In terms of long epic novels in a fantasy setting, Id also recommend the Malazan Book of the Fallen series by Steven Erikson.
Its got more magic and gods than SOIaF (at least what Ive read of SOIaF so far), as does Wheel of Time but Im not sure if that makes a difference? (I cant remember if Ive read Assassin's Apprentice or not to compare...)
Btw if you do look for it, dont get confused by the second author... Theres another guy, Ian C Esslemont, writing an "a novel of the Malazan Empire" series which is in the same setting. You want to start with Erikson, imo.
I don't think I've heard of The Wheel of Time. Is that the book where people serve out prison time by walking in order to rotate a large wheel/cog?
No, Wheel of Time is a standard epic fantasy story, with a young farm boy discovering a greater destiny, etc. In terms of standard fantasy theyre quite good, but the later books get bogged down pretty heavily in politics and who is doing what where without advancing the plot much... Which I get the impression is a bit of problem with the later SOIaF books, too.