the franchise is most certainly NOT "done"
Origins movies are in development for at least Magneto (others are strong possibilities, Storm, Deadpool... (yes i know he's not an "x-man" as such, but his strongest ties are to Wolverine and Siryn, both X-characters))
Not to mention of course, the forthcoming X-Men First Class... which is due in cinemas early-mid 2011... and starring, among others, James McAvoy as a younger Professor X...
at this stage, thank goodness, no Jean... but Storm, Cyke, Emma Frost, Beast (pre-blue fur i believe), Mystique, Toad, Havok and others have been included, some have even been confirmed as cast.