Fallout: New Vegas.
When it first came out, I was incredibly disappointed in it, I found the new crafting options needlessly complicated, the story uninspired, the graphics dated, the radio playlist unforgivably short and lacking in any really good songs that even remotely fit the setting (seriously there are three songs on the main radio station that feature yodeling and absolutely zero songs by Elvis, despite a large gang of Elvis impersonators featuring prominently in the city of New Vegas itself) and the absolute dearth of memorable characters to be just the final nail.
I didn't even bother to finish it the first time around, and then recently, after being horribly disappointed with Red Faction: Armageddon, I tried New Vegas again and lo and behold, it was a hell of a lot better than I remembered it.
Granted, all of the above issues were still issues, but I found I didn't nearly mind it so much.
The moral of the story is, if you have an old game that's pretty good but not great, buy Red Faction: Armageddon and make that old game look fucking spectacular by comparison!
(I will not forgive RF: Armageddon. Linear like a string is not necessarily bad, more heavily based in a single story is not necessarily bad, cave levels are not necessarily bad, but when the linearity includes punishments for leaving the beaten trail, when the single story is fucking abysmal, featuring characters that are blatantly retarded, bland like unflavored yogurt and ridiculously unlikeable and you spend nearly the entire game in a cave - in a series that is devoted to blowing up buildings, no less - there, my friend, is a completely unforgivable game. Better names for this game would have been Red Faction: Everybody On Mars Is Retarded or Magnet Gun: Someone Put This Weapon In A Better Game.)
