Rayman I've had on PSX for ages but never really played. I feel ashamed. I do have the new game, though, and it's marvelous. Best console 2D platformer to come along in a long while.
Mega Man Zero Collection I've been slowly making my way through. Pretty awesome stuff.
Lotta games mentioned that I haven't played.
Ghosts'n Goblins series is hard, but I do enjoy it, just never put in the effort to beat one of them. I just played through the arcade Bionic Commando once I heard the same director for G'nG and Tomba! was responsible for it. Definitely feels a lot like the G'nG games, and is hard as hell—I can't imagine anyone getting through it on one continue 'cos stuff's always coming at you and it seems almost impossible to avoid. But it's suuuuper short, so if you do manage to master it, you don't have very far to go. Ah, old school arcade games... Difficult for no reason than to clean you of all your quarters and tokens. Shame there never was an expanded console port of Bionic Commando. The NES game's better, but the original's certainly interesting.
One game I played recently that really blew me away is Aliens: Infestation on the DS. One of the most satisfying gaming experiences I've had in years; I played it for several hours straight and beat it the day I got it, which I rarely ever do anymore. It takes the few elements from Alien 3 on the SNES that didn't suck, and puts them in a game that feels more like Super Metroid with some Contra touches. Beautiful.