If either Mark, May or Alan had to die, who would it be?
Alan. Mark dying would be boring and May dying would just be a waste when she has all this character development to go through.
And how do I get the picture on my signature to not have a white background?
By making a picture that doesn't have a white background. Get a good paint program that can create transparent images, if you're using Paint.
Speaking of Colosseum and XD, what are your thoughts on them?
They were fun, atmospheric and had awesome music. I'd have liked them to be a little more properly story-based and I hated Poké Spots, but otherwise I liked them. Though I never got around to finishing XD; it was one of those games I went through training everything I got and I was somewhere on Citadark Isle with grossly underleveled Pokémon and kept losing to one of the Cipher guys. I'd like to see Genius Sonority make another Pokémon console RPG.
Oh, one other thing. What was your team on your first playthrough of Diamond / Pearl?
Something like Infernape, Staraptor, Luxray, Scyther, Gastrodon and Roserade. Later I added several more and started to rotate them (Butterfree, Leafeon, Charizard, Jolteon, Espeon, Lucario…).