Voltaire has some awesome songs. Some of my favourites are:
The Man Upstairs
Dead Girls Like Me
Sexy Data Tango
U.S.S Make Shit Up
Worf's Revenge (Klingon Rap)
When You're Evil
The last one isn't particularly funny, but I looove playing villainesses, and so "When You're Evil" is definitely a favourite because it so puts me in the mood! MC Chris is also a good one. "I Wanna Be a Stormtrooper", "Geek" and "Fett's Vette" are all awesome. For the Star Wars fans out there (I'm a huge Star Wars geek, oh god) there's "Star Wars Cantina" by Richard Cheese and "Star Wars Gangsta Rap". The last one has a flash video complete with dancing stormtroopers.
And, of course, for all the Canadians out there, there's The Arrogant Worms,m with such awesome titles as "Me Like Hockey" and "The Mountie Song".