I have too many wii games, so I have postponed buying the big title ones until I give enough time to at least figure which ones I like and don't like. However! I will make an exception for mario kart if someone in my family decides I need to have it for my birthday :P. Anyways the reason I'm even blogging about something I haven't tried is cuz I found some info on it you might like here:
Btw mario kart is pretty much the most awesome game evar. :) Tho smash bros. is a close call. I wish, want, desire, covet, whatever, that wii had xbox's standardized live service. It would be the bomb. However random matches with strangers sound like they are supported in the game.