For those inclined to black or dark desktops, here are six nice Firefox themes you want to give a try.
Pictured here on Windows XP with the Royal Noir theme for darker effect. All available from Mozilla Add-ons, but for those marked experimental you will need an account.
avant.garde.10011:nerom created by Rob Holian. (experimental)
Black Steel by Ben Griscom. (experimental)
Dark Revisited by Matthew Baerbock. (experimental)
Gradient iCool by Edward Mak.
Midnight Fox by TwisterMC.
Ruler Dark by dkgo. (experimental)