Only bands because solo artists complicate things.

Arcade Fire
Built To Spill
The Clash
Dirty Projectors
The Exploding Hearts
The Fall
Gang Of Four
Husker Du
I Hate Myself
The Jesus And Mary Chain
The Kinks
Low
My Bloody Valentine
Neutral Mill Hotel
Orange Juice
Pixies (choosing between Pixies, Pulp, and Pavement is picking a child to kill)
Quickspace
R.E.M. (R.E.M. and Radiohead are both top 3 bands of all time this is just cruel)
Swans
Talking Heads
Unwound
The Velvet Underground
The Wrens
X
Young Marble Giants
The Zombies

Obvious list.

For 'G' i actually thought of putting G-unit :p:

I had that thought about a few letters too! A hard choice between Swell Maps, The Smiths, The Slits, or Sugar.
Ditto for Television, Talking Heads, Thee Oh Sees, or Tegan & Sara

A - Absu
B - Blind Guardian
C - Catuvolcus
D - Death
E - Ensiferum
F - Forefather
G - Gallowbraid
H - Hail Spirit Noir
I - Immortal
J - Janvs
K - Kalmah
L - Lich King
M - Manegarm
N - Nocte Obducta
O - Overkill
P - Persuader
Q - Queen
R - Rotting Christ
S - Sigh
T - Transcending Bizarre?
U - Ulver
V - Vreid
W - Wintersun
X -
Y - Yngwie Malmsteen
Z -

This thread is even worse than the eighties survivor one. It's sick.

If you really wanted to make it challenging we shouldn't repeat bands previously mentioned.

Aside from many of the other awesome bands on your list I love that you included Vreid. I've only heard a little of them, but what I've heard is pretty fantastic.

That's right, the 'S' was really tricky with the Stranglers, the Smiths, the Stooges, the Sex Pistols, so on, as well as the 'D' and 'P' and with some letters you almost have no choice

Q, X, Z, were a little troublesome for me, some ppl are skipping them

Thank god for Queen xD

yes, that's why the list is not quite fair on some bands ...