I still remember this image (well, the one I remembered didn't have a question mark on it and it was on IGN):
http://www.kasuto.net/image/archives/news7.jpgWhen I first heard that Sega was going out of the console race to develop for all consoles, I thought back to how I loved Ecco the Dolphin (a Sega franchise) and Tails from "Sonic the Hedgehog 2". So I decided that since Sonic games would now appear on Nintendo consoles, I might as well drop the grudge since the two are no longer fighting and experience what I missed out on.
Man am I glad I did. Sonic Mega Collection has quickly jumped up to be one of my favorite GameCube games of all time (until Prince of Persia: Sands of Time and F-Zero GX came along).
I can't say I'd like to see Mario and Sonic together because, while it would be interesting, I can't imagine them cooperating. Sonic loses patience in two seconds, so he'd never stick with someone slow, and Mario would rather be at home doing plumbing stuff.