Half-Life 3, eh? Sounds interesting. I must have missed that one.
None of the items on that list are my favorite, as they are all too new, heh. If "favorite" is taken to mean the game I can consistently play through the most, I suppose my favorite game is either Mega Man 3 or Super Metroid. I probably play through that gem at least once a week. If it's the game I look most fondly on playing through, it'd probably be a tie between several games, including Baldur's Gate 2, Chrono Trigger, and Final Fantasy 4... and I guess Mega Man 3 and Super Metroid, as well
EDIT - Also, I'm moving the thread to the Video Gaming section. It seems more at home there.