Anyone but Alistair is fine, what a loser he is. Sorry buddy, I can see that you're a frail little flower using self-deprecation to hide from your shame, but it doesn't actually make me respect you as a human being.

Shale is the best (of course) in an independent sense, but I prefer Sten's interactions with others. Have to have a mage, obviously. My "ideal" party if I were to replay, for maximum combat balance and non-Alistair-related banter, would probably be Morrigan, Sten, Leliana, and obviously I'd be a mage personally.