I've been fooled and decieved by guys corny lines before, so I really don't know how i should take this one:
"It was only after I first e-mailed you that I noticed you weren't even in the same state as me--lots of cursing ensued. Then it turns out that you have an awesome personality, great sense of humor, and just so happen to be an anime chick! If I had my choice of having any girl as my special other, you'd be number one on my list. Honest to God"
Maybe you should let things go as they are for a while, keep talking to him but don't make any moves just yet. See how things go in a while, see what other signs may appear. Being too quick to make a move can be worse than doing nothing.
I dunno, sounds a little fishy to me...
But what if I wait too long and he's found someone else?
This guy out of his mind. Letter awfully badly written. "honest to God" oh puh-lease! Lets have him be honest to you first, no? He can judge your humour and like it, also that you like anime, he can know that. But can he know you? your personality? He not even know what shoes you wearing! What does he really know, about you, about love - about what it takes to love? Of course, not whole letter posted here, so FO can't make to much out of him. Still, it sound immature.