Of the above, I'd pick Baldur's Gate, which did a good job of closely following the original AD&D rules.
However, I highly recommend adding Neverwinter Nights to this list. Fuborc, if you haven't picked it up yet, I highly recommend it. The 3rd edition rules take a little bit to get us3ed to if you've played AD&D for a long time, but it's a great game. And with the ability to create your own adventures, have somebody Dungeon Master them, and download adventures made by other players, this is a game you could be playing for many years to come!