Who has the best stylesheet? Can someone tell me which site I can go to!

Use google. Or, you could make one yourself. That'd be the right thing to do.

Try looking at tutorials on W3 Schools on all the properties of CSS so you can make your own stylesheet. Or you could go look through some Xanga layouts here on cB and skim their stylesheets to help you. Although, you should first ask the creator if they'll give you permission to use the stylesheet. You could also try what Cheyenne said, search up some tutorials on Google or something.