The games you've listed are good choices,

Wind Waker is a game you can't miss

I would recommend you getting Time Splitters: Future Perfect over Time Splitters 2. The humor is spot on and it improves in every way over its predecessor.

Other than that you won't be disappointed with a great lineup like that. ^___^

You have to have

Resident Evil REmake - of course you thats only if you like that genre

I thik everyone else covered the rest pretty well

 After playing the Mega Man X games on SNES, I'm not sure I can bear playing a Mega Man game without dashing nor wall climbing, though. Also, I don't think it necessary applies to old school, but generally I like 2D games (I have skipped almost the whole last two generations, although it's mainly because I didn't have the opportunity...)

There is a Mega Man X Collection, but I think I will get a PS2 version instead since I think PS2 controller fits more...

Anyway, I guess there aren't many gamecube games left to list....

Pikmin 1 is a must get (I loved this game)
F-Zero GX is also a must buy (You could play this game for a very long time)
Super Monkey ball 1 and 2 are also great fun
DK Jungle Beat (another really good game)
Donkey Konga 1 and 2 (if you have friends who like Guitar hero, they'll probably love Donkey Konga as well) just make sure you get at least 2 or 3 bongo's

I would suggest Gladius and Second Sight (if you don't have them for another system) to go along with what everyone else has suggested. I didn't like MGS: TS very much. But those are just my opinions. Beyond Good and Evil and Metroid Prime 2 are must buys.