I like being a guy for lots of reasons: I can pee standing up, I can spit without people being really surprised, and I am a lot more popular with gay guys than I would otherwise be. Another quintessentially "guy" thing is our "y" chromosome (pictured) -- which stands alone as the only chromosome without a matching mate.
New research is indicating that the male "y" chromosome is evolving faster than any other chromosome in the bunch. Not exactly sure what that means, but I think that's cool, too.
You can read more about this research here.