I'm a big fan of
http://www.freecsstemplates.org/ for my websites. I've used it on three different sites, now, three different templates and haven't had much of a problem.
One problem I do find is if I use the 'post' area to create more than two seperate h3 headings, it mucks up the coding of the site completely, so I try to avoid that. Other than that, no problems.