Just like the title says. Only one band each letter.
A - Aerosmith
B - Bob Marley
C - The Clash
D - Dir en grey
E - Eugene Huetz
F - Faith No More
G - Green Day
H - Hans Zimmer
I - Incubus
J - Jimi Hendrix
K - Kagrra
L - Luna Sea
M - Marvin Gaye
N - Nirvana
O - The Offspring
P - Pink Floyd
Q - Queen
R - Radiohead
S - Smokey Robinson
T - Tool
U - U2 I guess.
V - I got nothing.
W - Weezer
X - X-Japan
Y - I got nothing - maybe Yngwie Malmsteen.
Z - I got nothing.