Ya a lot of my friends have told me the same. I don't quite know why I didn't play it to be honest. The trailers and everything had me pretty interested and then somehow it kinda fell off my radar. By the time I thought about picking it up again I couldn't find a copy anywhere.

I missed out on many games that I would have liked to have played when they were new. It's much harder to play games that are 10-15 years old now.

The Metroid games on Gamecube
Chrono Cross

I haven't had any luck getting a DS3 to work with my PC, although I admittedly didn't try very long or hard.

pong
viva pinata

not many.
So far only Mass Effect 3, which I haven't played yet for savegame reasons.
Once I played through ME and ME2 again, I will get my hands on ME3.

Classic jrpgs such as
FFVI
FFVII
Chrono Cross
So many of them :/

The better SNES games released late in its life time (I was more of a SEGA guy)
All the amazing Japanese Saturn games (I didn't get into importing until Dreamcast)
I also regret never owning a GCN, was the only "big" console I have never owned. Twin Snakes is probably amazing.

There's a lot. Off the top of my head there's:

Okami (supposed to be beautiful and Zelda inspired, I should really play this game)
Earthbound (A SNES RPG, I love SNES RPGs)
The Last of Us (I loved Uncharted and the demo but never picked up this title because I've got so many games to play already)
Legend of Zelda: A Link Between Worlds, Super Mario 3D Land, Pokemon, Mario Kart 7, NSMB2 and possibly more (Like I said before, I've got so many games to play, I can't justify the purchase of another console)

Ico and Shadow of the Colossus - At the same time though, I'm not sure I want to play them, no matter how good they may be.