It's just a pet peeve but I can't stand band names that are just bastardized versions of other artists and people's real names.
Examples:
Joanna Gruesome
Joy Orbison
Wevie Stonder
Bitt Meddler
Buckcherry
Pamela Lansbury (Glee)
Another thing that annoys me is bands that use female imagery in their names but don't bother to include any women in their band. Like Girl Talk for example... there are much better examples but those are bands that go in one ear and out the other so I can't think of them at the moment.
The third thing that really annoys me is bands that use the name of a city, state, or country who have absolutely no connection to that place and aren't from there. Like, what? The twin virtues of being both meaningless and misleading.
Of course, a band with an awful name can still be amazing, and a band with a great name can still suck!