How about let's get a list of who actually uses Visa, huh?
As to Mac's being stable/virus free; the campus I'm on had a nasty outbreak of Mac viruses last year, after a Mac user got infected and spread it throughout the network. As to them being stable, my roommate managed to crash his Mac within the first week of having it. Then, about two weeks ago, he turned it off, moved to a new location, and it was dead.
But these arguments bore me, if you go to any sort of tech campus you get tired of hearing them, and honestly, it doesn't matter either way. It's down to personal preference, and if Mac users (and I say Mac users because honestly, you'd have to look relatively hard to find a PC user who's so dogmatic about the platform) would just shut up about their platform being "superior" then we could move on with their lives. I'm not saying it is or isn't, I'm just saying shut the hell up about it. You're the Abercrombie and Fitch of the computing world and all you do is serve to annoy people who either don't care or actually know what they're talking about (on both ends, Mac or PC).