Just recently, I finished what I'd call optimal Baldur's Gate 2 run, so maybe I can give you some advices. You probably already know most of what I'll mention, so I am sorry in advance for being often reduntant.
For easier combat, use your spellcasters for party defense and enemy debuffing. Offensive magic is of lesser importance. Also some summon spells can make a big difference. Some important spells: Stoneskins, Iron Skins, Mirror Image, Haste, Lower Resistance, Greater Malison, Remove Magic, Breach, Insect Plague, Aerial Servant, Animate Dead, Call Woodland Beings, Mordekainen Sword. Also, remember that power of some spells is level-based, so the spell which initially seem weak, can become quite powerful later. Probably the best example of such spell is Magic Missile - later dragon killer. Some enemies can't be hit by normal weapons, so you need enchanted ones. Some golems can be hit only by blunt weapons. Best shop is Adventurer's Mart in Waukeen Promenade, and (after freeing slaves there) Copper Coronet. With a well geared and spell protected party most of the combat should be less tedious and shouldn't stand so much in the way of those more roleplaying aspects.
Well, even though combat eventually stops being tedious and ideally starts to be fun, vanilla BG2 isn't that rich/mature/immersive experience as one would wish (and think, based on the hype). I personally wasn't much impressed with my first playthrough years ago and thought that the game was overrated. Now I find playng BG2 to be pretty entertaining matter and the reason is simple: mods. With the vast amount of them, you can quite substancially enhance and optimize the game for yourself. So, here's my suggestion for some of them to make your possible playthrough more entertaining.
First, some links to the main modding sites where most of those mods which I reccommend can be downloaded:
http://www.gibberlings3.net/
http://www.pocketplane.net/mambo/
http://www.spellholdstudios.net/
Now for mods themselves, listed in recommended order of installation:
(the letter in parentheses indicates the download location - G for Gibberlings, P for Pocket Plane, S for Spellhold)
1)for additional bugfixes there's BG2 Fixpack(G), this is a must
2)additional quests/encounters:
Longer Road(S) - main villain of SoA can join your party in ToB expansion, although it may sound a bit ridiculous, the mod is actually one of the best written ones, adds a lot of roleplaying possibilites, complex dialogues, quest and greatly enhances otherwise quite shallow expansion, it has four different endings, based on your actions - for me an absolute must, otherwise the expansion is just bleak
Romantic Encounters(G) - adds very well written and mostly funny encounters
Dungeon Crawl (P) - adds voiced and really funny quest with a bit of different flavour
Well, for the first playthrough I wouldn't recommend installing more but I also like: Unfinished Bussiness(P), Quest Pack(P) , Fading Promises(S) and Ascension (
http://www.weidu.org/asc.html - this one is a must for me because it further enhances the expansion and makes the final battle MUCH more memorable, but also pretty damn difficult, so install at your own risk, if so, this mod should be installed right after the Fixpack)
3)NPCs
This is the kind of mods that make the game much better, keep it fresh and increase replay factor the most. Here are some of my suggestions:
Xan(P) - depressive mage from BG1, with original voicing, vast amount of dialogues and three quests, he is very well written, with plenty of player dialogue options, if you appreciate this kind of character, he is entertaining for the whole run, even moreso if you make him wild mage during the installation
Kivan(G) - melancholic archer elf from BG1, well written, interesting personality, sometimes gives you bad advices which is refreshing
Hm, actually I consider all NPC mods which I recommend to be well written, so I won't be repeating it in their descriptions.
Keto(P) - a bardess, with astonishing voicing and impressively scripted quest with four different progressions and lot of singing too, SoA only
Angelo(G) - personality-wise probably the coolest NPC available, some very funny dialogues, well made quest, lot of ToB content, his fighter/mage class also makes him a viable choice for a tank, has original voicing
Now, assuming you're playing a male protagonist, here are two good mods with possible romances:
Amber(S) - well voiced female fighter/thief with elaborate quest, her romance is really nice, SoA only
DeArnise Romance(P) - adds a romantic possibilities for vanilla NPC Nalia, although her vanilla character is underdeveloped and her stats nothing to call home about, the romance is the best avaiable imho, it is quite dialogue heavy, but the content delves relatively deep, has some philosophical extensions and the best part is the amount of player dialogue choices which are far from usual yes/no, good/evil binaries, SoA only, though Nalia has some vanilla content in ToB - I really recommend trying this one, it is certainly the most mature romance available
Those NPCs which lack ToB content can be replaced at the start of the expansion with one new vanilla NPC, and if you install Longer Road, with the another one.
Well, to make your party feel more alive, there are some additional banter packs which help it.
Banter Packs(P) - adds banters between vanilla NPCs - a must
Flirt Packs(P) - adds flirts for vanilla romanceable characters - if you don't plan to romance any of them, it is redundant, otherwise it enlivens romances pretty effectively
Crossmod Banter Pack (G) - if you plan to have more than one of the mod NPCs in your party, you should install it because it adds banters between them
4)Rule changing/additions/tweaks
Rogue Rebalancing (S) - thoughtfully rebalances thief and bard classes, adds more possibilities for thieves and also adds easily the most elaborate encounter in game, I wouldn't recommend installing its Shadow Thief Imrovements component because it can make some battles pretty hard, on the other hand its Cyric Encounter is a true delight - it is very atmospheric, has great roleplay value and quite a few different outcomes
BG2 Tweaks(G) - this is the mod that can reduce quite a lot of tedious aspects of the game - there is a lot of cool components in this one, such as unlimited item stacking which reduces inventory juggling, gain max hitpoints at level up which reduces possible reloading, shut up "you must gather your party" and many others, some components are pretty much cheats, so don't install those, read the readme carefully for this one
OnePixelProduction aka 1PPv2(S) - changes horrible paperdolls to much better looking ones, as well as some inventory icons and in-game avatars - quite necessary
Refinements(S) - I recommend only its "New HLAs Tables for all classes" component from this one, but its a pretty major one - it makes later stages of character development much more interesting, varied and helps some classes to be more distinctive and useful, it obsoletes some changes from Rogue Rebalancing but these two mods work well together
Uh, I got a bit carried away, I see.
Anyway, if you install all of the above mods (on top of the patched SoA with ToB), in the same order as I've listed them, there should be no compatibility problems. Installation is usually straightforward, but of course, always read the readmes before installing.
I believe that similar mod setup makes the game much more interesting and in a sense almost postmodern experience. Reserve some quiet Sunday afternoon for it and mod the shit out of Baldur's Gate 2, I say!
For a good entertaininment value I recommend having modded Nalia or Amber as a romantic interest, 1-2 of the other listed NPCs and the rest spots reserved for some vanilla ones. Try Jan Jansen, who is waiting in the middle of the Goverment District, for a while - he is probably the most original of the bunch. If you choose not to play one of the suggested romances, maybe you should try Viconia, out of the vanilla ones, this is the least annoying. Or simply don't romance anyone.
As for the protagonist's class, if you want to have a diverse one, I'd suggest either ranger/cleric multiclass or skald. Ranger/cleric has access to all druid and cleric spells, so you don't need to have another one in your group and is also a very good tank, his usability is very diverse and should be fun to play. With Rogue Rebalancing installed ,skald is maybe even more diverse class, but probably a bit more difficult to use effectively. Spells, lots of weapons, bard song and great high level abilities from Refinements make this class really a blast. This class levels up very fast, which makes some of its spells more useful. With bard you also have a chance to run a theater which is also the most entertaining stronghold quest in the game imo.
Right now, if I wanted to play with a functional and engaging party, I'd probably play a ranger/cleric protagonist with a party consisting of Angelo, Nalia, Xan, Yoshimo and Kivan/Jan Jansen. For ToB, I'd replace Kivan/Jan and Nalia with the new mysterious vanilla NPC and the Longer Road one.
All in all, I am pretty sure that well chosen mods can elevate only average original game to a very good one.
Alternatively, you may try BG1 in Tutu conversion with BG1 NPC mod installed.
Hm, I better stop now. Sorry, for my overlong babbling, but maybe you'll find some of it useful. Oh, and sorry for my engrish, I am bat at it.
Wishing well!
P.S.: Even heavily modded, I still don't consider BG2 to be a pinnacle of computer gaming entertainment, but if in the right, and a bit childish, mood, I find it to be overall a very pleasant experience. When I want to play some really engaging computer game, I load up either Planescape: Torment or Minesweeper.