I cast my vote for G2 (especially with Notr added).
I love the entire gothic series and when the first one arrived it completely blew me away. Going down that winding road and discovering a big city with lots of interesting NPCs with their own daily tasks reminded me of "Ultima 7 Serpent Isle" - just in full 3d
Later, when I found myself sneaking around the woods at night hunting scavengers with a bow and trying to avoid roaming wolf packs and sleeping shadowbeasts it just hit me - this was the most immersive RPG I had played for a very long time. I felt like being a part of the world!
When G2 arrived I basically just wanted more of the same - and in my opinion that's pretty much what we got, just bigger and prettier
Now, for me both the story and the exploration part of the Gothics are the most important things - possibly with exploration being the most important one for me. And this is what tips the scale towards G2 for me I think. I just *love* walking through the world, looking for small hidden caves or tombs. As cliche as it might sound I *love* finding hidden caves when I swim behind a waterfall
G1 had some of these locations, but G2 was just completely *stuffed* with them. All designed by hand and with carefully distributed loot to be found. One of the best examples is the treasure island in G2. I was standing at the harbor, looking out over the open sea - and there in the distance there seems to be an small island. I swim to it and find it inhabited by a pack of beasts which I manage to defeat. Then I find the hidden entrance to a treasure cave, complete with a spike trap, hidden switch and everything. I mean, what's not to love here
G3 is also great. It's absolutely huge, looks great and also has lots of secret caves to find. Unfortunately there are way too few items in the game, so you very very rarely find any really interesting loot. Also the content of the chests has been randomized (there are probably too many for the devs to fill manually), which in my opinion also makes it less interesting to go exploring for them.
So, bottom line - G2:NOTR is the best Gothic for me