If you're the sort of person who knows their Frappucino from their chocolate mocha, then this Coffee Theme could be for you.
The Series 60 theme comes with an attractive brown background featuring lots of funky swirls and wavy lines. All of the menu text is changed to various shades of brown, making for an interface that looks good enough to drink. The theme also adds a new clock skin (and guess what? It's brown)
Another great thing about the Coffee Theme is its menu icons. These new icons are bright and colorful, and offset the brown very well.
If you don't like brown then don't bother with this one, but coffeeholics should give Coffee Theme a try.