You should have a balanced party. Social skills are party-based AFAIR, so it is enough to have one charismatic talker. Only exception is flirting (I don't know how this is translated), which is dependent on sex, so if you want it fully balanced, you have a male and a female flirter in your party (not that you get to use the skill that often anyway). Barter is also useful, especially in the beginning. But even later, when you accumulate hundreds of gold coins, there will be some items that will cost almost everything you own.
Very important is to have healers and crafters. Especially later in the game you can make your life much easier, since you can craft some powerful weapons, and can produce your own healing potions and salves. One of your characters should be good at lockpicking, and someone should be a good spellcaster. Unless your PC is a mage, it will take a while until a capable mage joins you, though. I don't regret my choice of playing a mage myself. There are three NPCs which can be turned into good front liners, and two thief-like characters.
I didn't use sneaking very often.