Sorry if this isn't original, but I've looked around for this topic and couln't find it. Here are my ranks:

1 - X-Men Days of Future Past - a much relevant entry that future proofs an old franchise by correcting its issues with an unified concept and a solid cast.

2 - X-Men - a classic comic book movie with a central villain, the characters' introduction and a clear concept carried by Wolverine and Rogue, as well as the politics that define this comic book franchise.

3 - X-Men 2 - slightly worse than X-Men, in my opinion, because it lacked a believable villain who could stand up to these mutants. The mutants being on one side didn't help the political dynamics of this franchise.

4 - X-Men Last Stand - While the characters didn't feel right, the movie improved the pacing and action from X-Men 2 with the polished visuals X-Men could only dream of at the time. Sadly, they don't make a movie alone.

5 - X-Men First Class - Sorry, I didn't buy the references to the old movies, and would rather consider this a lame attempt at pleasing the fans. The mutants' presence in history was given too much importance by having them shape its events, instead of just participating in someone else's conflict like they did in DoFP with the Vietnam War. It downplays their secrecy and political stance when they are used as cool government weapons.

6 - X-Men Origins: Wolverine - Far too contrived for its own good, treading old ground and explaining things when it wasn't necessary, and with awful pacing.

1 - X-Men Days of Future Past

2 - X-Men 2

3 - X-Men

4. - X-Men First Class

5 - X-Men Origins: Wolverine

6 - X-Men Last Stand

1. DoFP

2. First Class

3. X2

4. X-Men

5. Last Stand

6. Origins

DOFP - Fabuluos

First Class - Fantastic

XM - Good

Origins - OK

X2 - Not that bad

Last Stand - Ugh

They all were pretty awful but if I had to rank I would say:

1.) Last Stand

2.) X-2

3.) X-1

4.) First class

5.) Dofp

6.) Origins

There has never been a X-Men movie but to answer your question:

1. Wolverine: Days of Xavier and Magneto's Past

2. Xavier and Magneto: First Class

3. The Wolverine

4. Wolverine: The Last Straw

5. Wolverine

6. Wolverine: Ghosts of the Past

7. Wolverine: Origins

He he, keep them coming!

1) DoFP

2) First Class

3) X1

4) X2

5) The Last Stand

6) Origins