Wow, OSX is ahead! Color me impressed.
OTOH, I'm sure this is not a representative sample of Mini owners. Let's face it: enthusiasts and hackers are more likely to visit a forum like this than your average user.
Still it's impressive that so many are running OSX on their Mini 9. Just a shame that Apple doesn't license the machine, slap an Apple logo on it and sell it themselves. There' d be no development costs, and I seriously doubt it would cannibalize sales of other Apple products. I could see a 10" or 12" netbook hurting Macbook sales, but not a 9" netbook like the Mini 9.
As for me, I'm currently running Ubuntu, but will probably move to XP once I figure out why I'm having trouble with my install procedure.