^Which goes to show just how far Cyclops has fallen that Magneto is even now part of the X-Men.
From the sounds of things, I may have to get back into the X-men. What is the best title to collect?
Uncanny X-Men and "Wolverine and the X-Men" are the main books. Uncanny X-Force is also very good in terms of storytelling.
Also you might want to read Grant Morrison's run on X-Men v2 and House of M. Then follow it up with Messiah Complex, Utopia and Second Coming.