I've never actually watched the earliest of Disney's cartoons like the black and white Mickey stuff. 
Mind you I was aware of the cartoons just never got around to watching them as  a kid).
So the first time I ever heard the phrase "Steamboat Willie" was from the following video: 
  http://www.appsro.com/cartoons.aspx 
Oh and this might be a bit NSFW at least in terms of dialogue, nothing graphical.

I was lead to the site after finding a link in one of the artists profiles who make the animated stuff for the Escapist and thought some of his stuff was hilarious :) 
So of course immediately after hearing the words Steamboat Willie on the Giantbomb E3 coverage this is the thing that popped into my sick head. Since this was my first exposure to the phrase it is now forever associated with the cartoon in my mind.
I think it would actually make for an interesting flash game where you had to make money with Mickey to survive, heh heh.
To those of you who grew up with the b/w Mickey cartoons or just had him as a big part of your childhood, does it make the cartoon in the link even more funny? 
 
Ahem. hope this isn't considered spam :D