I originally placed this in another thread, so I'll enter my post here.
I was going over the timeline discussion for a while, and, while it is a mess, this is how I would view the 9 movies once "Wolverine 3" arrives in theaters next year.
Start with the Original Trilogy: X1/X2/X3
then
the Wolverine Spin-off Trilogy: XO: Wolverine, The Wolverine, and untitled "Wolverine 3"
and finally
the First Class Trilogy: X: FC, X: DoFP, X:A.
Deadpool, untitled "Deadpool 2", and "Deadpool 3" will continue the saga in present day and will probably be its own thing.
Hopefully, this method would cause the least amount of headaches when following the entire saga. I hope to see the movies broken up into trilogy box sets including the upcoming Deadpool films. Is X-Force essentially going to be "Deadpool 3"? What about the New Mutants?