Being a former San Franciscan, I took note when Marvel decided to move the X-Men to San Francisco, and thought, hey, maybe that's a story I should read some time. After reading and enjoying Matt Fraction's X-Men: Nation X earlier this year, I decided that maybe it was time to go back to the beginning of the X-Men in SF story.
The basic story is: After previous Big Events (X-Men: Messiah Complex), the X-Men move to the Bay Area, buying up all of the military bases that dot the Marin headlands in order to create a complex/sanctuary for any of the remaining mutants who would like to join them. This book initially spends quite a bit of time on Pixie, a newer member of the X-Men team, but Cyclops, Wolverine, and Emma Frost form the backbone of the book (and this rebooted, relocated team). While this book is mostly about new beginnings, the team does face a threat in the form of the Hellfire Cult, who are determined to eliminate the mutant "threat" once and for all. The book ends with shorter slice of life/character study stories, which don't so much add to the plot as give you a deeper understanding of several of the characters.
I really, really enjoyed this book. While I'm starting to learn more X-Men canon, I'm still a relative newbie to their slice of the comics world, and I was easily able to follow along with the characters/plot/etc. So, if you're just looking to get started on the X-Men, this book is a pretty good entry point. I would imagine that if you aren't a beginner, it's just as good and satisfying a read.