Of Montreal is good, but Opeth deserves that spot. >:C
In Flames could be replaced with Iron Maiden, and it would still work.
And Metallica is not M? WTF?
L=Lacuna Coil, definately.
Nice choice on Kaizer's Orchestra btw. They're great. The rest of the list is pretty good too.
Floater, I'm just starting to listen to them because they've been recommended to me. They're kind of local, since I'm from Oregon. :)
I like The Decemberists :D
L - Lovage. <3
U - Underworld, if you're into electronica.
V - Verve or Veda.
X - Xiu Xiu (can't think of anything)
Y - Yo La Tengo(because I can't think of anything either)
Z - Zwan
Random list. :D