I have 11 and one test skin. The test will eventually be deleted, it's just my testing grounds for things.
I'm shocked at the response I thought people all had a bunch of skins on there board. Maybe it was unnecessary for us to make ten then. I just thought it was a good number.
I have 3, but I eventually turned two of them off, because a poll suggested that no one even knew we had alternate styles. I figured it would be easier to maintain being that I make regular changes to the forum and experiment a lot. But in the future, I plan on making my own skins, so I'm pretty sure I'll have more. Or I may see a free one that I simply can't resist.