Since "X2: X-Men United" in 2003 when Jean Grey disappeared, a few other X-Men movies were made with Wolverine gaining more onscreen presence. "The Wolverine" made a decade later, is sort of a spin-off movie due to Hugh Jackman's excellent portrayal of the character.
After what appeared to be Jean's death, Wolverine went into hiding out of guilt. His recurring nightmares of Jean beside him, night after night, turned him into a recluse. That was when he was brought to Japan and met Mariko, his love-interest in the comics. I didn't quite like the storyline though, with the Yakuzas and ninjas and the Viper.
For me, the best part of the movie was the easter egg segment, where Magneto and Prof Xavier appeared, and hinted of a huge storm brewing ahead of them, thus uniting both forces together to fight what was coming up.
This was where everything started. This so-called prequel to the X-Men movies chronicles a time when Magneto and Professor Xavier were known as Erik and Charles respectively. It traced back to when they first met as younger men and fought alongside each other before parting ways as enemies.
It explains how the two once close as brothers friends diverged on separate paths and why Professor Xavier was wheel-chair bound and much more. Starring a stellar cast of James McAvoy, Michael Fassbender, Kevin Bacon, Rose Byrne with a hilarious less than 1-min cameo by Hugh Jackman, I enjoyed the movie because this is the origin of it all and it helps to explain the relationships between Magneto, Professor Xavier, Mystique, Beast etc.
There will be no spoiler alerts here but a link on the movie is attached below:
http://en.wikipedia.org/wiki/X-Men:_First_Class
The 2 posters of Magneto and Professor Xavier are also very interesting because the reflections in the water show who they eventually become.