For some games (like Mario 3 for example), the classic controller sucks because the configuration is awkward. But then you can still just use the wiimote sideways and that works fine.
I bought the classic controller, but I don't care much for it. I really wish I could plug my Gamecube crontoller in. I really don't like turning the Wii controller sideways.
My kids play the old games with the Gamecube controllers and they play great. Attach just like you said, although they use remote ones. The Gamecube games look much better on the Wii, IMO.
man i didnt know that. i really want to start getting into video games again, not sure to go with the wii or the ps3
If you're playing on an HD set, make sure to get the component cables as there is noticeable lag without them.