I was just young enough to miss out on the old Fallout games - although GOG.com is tempting me towards them. Fallout 3 is definitely top of my list.

I have to say that the worst decline in a game franchise is that of FInal Fantasy. After the Enix merger, Square started listening to the idiots who said the games "would be better" if they abandoned the series' turn-based random battle system. The result was the travesty that is FInal Fantasy XII.

Mainly Half Life 2, and TF2 whenever I get stuck on that's singleplayer.