Just came across this one and thought I'd share; always thought the borders were a bit thick in Vista under Aero, but they look much nicer when they're a bit thinner.
http://www.tkarena.com/Articles/tab.../mid/382/ArticleID/30/PageID/132/Default.aspx
http://www.tkarena.com/Articles/tab.../mid/382/ArticleID/30/PageID/132/Default.aspx