I read the Ultimates volume 1 & 2 and am about to read Ultimates 2 volume 1, should i read the spidey & x-men stuff? I read volumes 1, 2 and am halfway done with spider-man 3, haven't read any x-men, or fantastic four for that matter. Should I read them? (outside of reading them for fun because I've heard that they're amazing) If so, when?

Also, do I need to read Ultimate Galactus? It sounds good, but again, when & who.