I s'pose some of these aren't really "classics" but at the sort of prices they're going for it's almost rude not to...
Waverace
Star Wars Rogue Leader (though you may have to search for rouge leader on eBay
Could have been a good concept, stormtroopers with make-up)
Pikmin
Super Monkey Ball
F-Zero GX
Mario Kart Double Dash
Metroid Prime
Mario Golf
There are others that are worth a few quid, will need to think/rummage through cupboards !