1. Easy to pronounce.
This is why Mr. Mxyzptlk's Mystical and Majique Munnfunsters hasn't been burning up the local music scene.
2. Easy to spell.
See above example.
3. Easy to Google.
Naming your band "Free Beer" or "Lindsay Lohan's Tits" will surely make it more difficult for people to find relevant search results related to your group.
4. Easy to chant.
Two to three syllables is pretty good. As much as they rock, it's hard to get 5,000 screaming fans to all chant "AND YOU WILL KNOW US BY THE TRAIL OF DEAD!" in unison.
5. Easy to Acronymize.
BK. HP. DQ. It's the way of the future. (This doesn't apply if your band's name is ...And You Will Know Us By the Trail of Dead.)
I know it's difficult in this day and age. It seems all the good band names have been taken: the Rolling Stones, the Pixies, U2, The Fashion Coasters, Jesus Chavez and the One-Eyed Donkey-Lovers, et cetera, but do a little research before telling everyone that you think "The Jam" is a great name for your project.
7. Look good on a T-shirt.
Clothing is one thing that isn't available as a bit torrent or MP3, so you best make your apparel look sharp.
8. Represent Your Sound
There's nothing quite like hearing a great band name and then finding out they're not at all as clever, funny, or fun as the name suggests.