The new movie will focus on a new set of mutants in their teenage years, and according to produce Lauren Shuler-Donner, will have a feel much like the Harry Potter movies.
X-Men: First Class is also an 8-issue comic that first appeared back in 2006 and featured Angel, Beast, Cyclops, Iceman, Jean Grey, and Professor X. However, seeing that all of these characters have been introduced, killed, and reincarnated, I doubt the writers will want to keep them alive, even in their earlier years, with a prequel.
However, Bryan Singer also gave a really juicy quote regarding the plot and characters:
“[t]his is the formative years of Xavier and Magneto, and the formation of the school and where there relationship took a wrong turn … [t]here is a romantic element, and some of the mutants from ‘X-Men’ will figure into the plot, though I don’t want to say which ones. There will be a lot of new mutants and a great villain.”
I thought Bryan Singer was great, and really did a great job with X2: X-Men United. But when he gave up on X-Men: The Last Stand to do the shitty Superman Returns movie, I really was annoyed with him. Though I loved The Last Stand, Brett Ratner did a poor job with the movie overall. I hope Singer can step it up and deliver some awesome storyline with better effects.