Ooooh, I love doing these on Facebook every now and then, so let's see what I can come up with today:
Ayreon
Big Big Train
CIRCA: (not many choices here for me)
Dream Theater
Emerson Lake & Palmer
Flower Kings, The
Genesis
Haken
IQ
Journey (I guess? Not a lot of J-named bands in my collection)
Kansas
Liquid Tension Experiment (very relevant)
Muse
Neal Morse (Solo, NMB)
OSI
Porcupine Tree
Queen
Rush
Spock's Beard
Transatlantic
Unitopia (almost went with UK)
Van der Graaf Generator (I guess? Don't have a lot of V-bands)
Who, The
X___(I got nothing)
Yes
Z___(I got nothing again)
I knew the end of the alphabet would be a bit tricky, but the first-letter-of-first-name held me up a bit. Otherwise, I would have put Hans Zimmer for Z, especially since I organize my music by last-name-first in my collection. I guess I still could, since I seen some folks listing Zappa for Z, and not under F for Frank Zappa.
-Marc.