For me, the one that would be my favorite is Icewind Dale, mainly because it doesn't have many of the problems that the Baldur's Gate games have. Unlike BG1, you aren't stuck at a low level for too long (leveling up to level 2 before leaving the starting town is realistically possible), and unlike BG2, you aren't constantly interrupted by timed quests when you're trying to do other things, like manage your inventory and shop.
With that said, it still has some problems, like the fact that real time with pause combat just isn't that good, the fact that all movement relies on pathfinding (can't control your characters with the arrow keys), and that traps just aren't a good game mechanic (outside of troll games, which this game is clearly not).
Tuthrick: So, yeah I don't like BG2 - I was disappointed from my first experience when it came out. I wanted to give the game a fair chance, but in the end I had to force myself to complete it. Things I don't like about the game:
- character animations are mirrored (when they turn from right to left, they swap items in their hands) and they look worse than BG1.
- the artstyle: items, gui, portraits and locations. Some of these just look weird, or have really low quality.
- romances: never liked them, don't like them in most games. Planescape: Torment has shown a subtler and better written approach.
- very limited party composition options. NPCs have elaborate quests, but I find most of them unlikeable (Imoen is emo now, Jaheira is a milf, Minsc is a headache generator with all that yelling, Jan Jansen makes me cringe and so on).
- very unbalanced classes. Arcane casters rule the game so much it's not even funny, the rest of the classes feel like innecessary baggage. In BG1 archers are very powerful, but you are still fine without them. In BG2 I don't know if you actually can complete the game without a mage or a sorcerer.
- lack of freedom, the game is much more linear.
- There's something off with the writing and the lore. Artifacts get like two sentences, there's a focus on emotions and feelings in the storyline. The antagonist is just annoying and feels like an angry teenager.
I think I will stop here with BG2. Is it a bad game in my opinion? Of course not, but I prefer other cRPGs.
* Character animations are a non-factor for me in judging games.
* Artstyle is again a non-factor.
* Romances: There isn't enough choice in them, and the options are not inclusive enough. Male characters have 3 choices, but they're all female. Female characters have only 1 choice, a male character. To me, I would rather have no romance at all than only have straight romance.
* Class balance: This can be an issue (although it is fun being able to use spells like Chain Contingency that I haven't seen in any other CRPG, and Project Image reminds me of Romancing SaGa's rather fun Phantom Warrior spell, complete with the ability to copy consumables and use them without using up the real ones). One thing BG2 does well, however, is that every single multi-class combp has some neat synergy that you don't get with either class individually.
* Lack of freedom: There's actually a lot to do here. The problem I have, however, is that the game will start timed quests for you, and that gets rather frustrating and stressful, especially when I'm just trying to manage my inventory.
(With that said, I'd argue that it's still not as bad as Final Fantasy 7, and even that is still far better than, say, the NES version of Ultima 5 or Hoshi wo Miru Hito. Note, however, that the issues with those games are entirely different than the ones with the Baldur's Gate series.)
Edit: I find that IE combat is more enjoyable if I disable the ally AI; this is especially true if using a bard in Icewind Dale (with Heart of Winter installed).