'fraid not... as someone else hinted at, once you click start on the disc channel with a GC game in, you lose all Wii features (including the ability to return back to the Wii menu or turn the console off without getting up, even pressing the reset button on the console only resets the GC)

As such, if you don't have a GC controller you will have to buy one if you are planning on playing GC games... Unless you have lots of disposable income I would suggest trying out a 3rd party option as official Nintendo controllers are rare to the point that they cost over twice as much as they did when the GC launched... and unused wavebird controllers are pretty much non-existant.

http://www.amazon.co.uk/gp/search?ie=UTF8&keywords=gamecube%20controller%20wii&tag=509-21&index=aps&linkCode=ur2&camp=1634&creative=6738

If you are willing to buy 2nd hand though (the GC controller is sturdy, so the only problem will be if you don't like the idea of a controller someone else has sweated on) I would suggest going Wavebird, because wires are annoying.
http://www.amazon.co.uk/gp/search/ref=nb_sb_ss_i_2_8/277-8746704-3739557?url=search-alias%3Daps&field-keywords=wavebird+controller&sprefix=wavebird%2Caps%2C194&rh=i%3Aaps%2Ck%3Awavebird+controller&ajr=0

Sonic Colors

Hmm, If Mario and platformers aren't your thing, your choices on the Wii might be scant, since those both tend to be the Wii's bread and butter.. But here are some games I'd check out based on your prefered genres and some other random games you might like..

First off.. Mario Kart Wii is a MUST, especially if you like the Mario Kart series
Monster Hunter Tri
Metroid Prime 3, or Trilogy if you can get your hands on it
RE: 4 (if by some chance you haven't played it yet)
Little King's Story
Tales of Symphonia 2
Fragile Dreams
Silent Hill: Shattered Memories
Sin and Punishment 2
Muramasa
Mad World (while you can wax this game off pretty quick, it is a steal at the 9 bucks amazon sells it for)
Dawn of Discovery (not sure if you like RTS games but it is probably one of the best you'll find on a home console)
Red Steel 2 (nothing like the first Red Steel, and is one of the few Wii games that uses the Wii motion plus quite well)

also, look out for Last Story. From what I've played so far, it is a well made JRPG, if you don't mind the somewhat bland color schemes.

The sweet part is, you can probably find most of these games in the bargain bin now for like $10-$20 bucks.

I resent the £0.87 I ultimately payed for MadWorld... Only buy it if you really really like hack & slash style games.

The only reason I bought the Wii in first place was The Zelda Franchise. I play PS3 and PC most of the time but since my PC and my PS3 are in my apartment I don´t have anything on weekends when I am my parents place. So I thought I stock up my Wii collection but didn´t really any other good Wii games except of Xenoblade.

Get DKCR and Fire Emblem Radiant Dawn. 2 of the best games this gen.

Excitebots and NFS Nitro

quick reminder, not all wii's have gamecube backwards compatibility anymore. I wanna say either the mariokart bundle, or the new supermario bros bundle discontinued the functionality.

WHAAAAAT?

Good point, totally forgot about that... The blue Wii is definately not GC compatible anymore. (If when you buy it it mentions 'slim model' or 'slim style' or something similar then it probably won't play GC games)