Well, I have read the largest part of the X-Men, spin-offs and X-Men related comics, about up to 2003 I guess. An where you start is at The Uncanny X-Men #1 and that was the only X-Men comic for about a 150 issues and then came the X-Factor series and New Mutants series as spin-offs. I liked the New Mutants. X-Factor could be considered reasonable. Later you got a lot more spin-offs like Excalibur, X-Men, Extreme X-Men, X-force and X-Statix (cash in on the reality show bizz). Some X-Men got their own series as either limited or full-fledged, such as Wolverine (the longest running). I think Deadpool was still the best, although not actually an X-Men he is frequently associated with them. The Uncanny X-Men is still the primary series of the X-Men.
In the 21st century Marvel decided to restart some of their major series with updated looks and story telling, more based on the japanese manga style. And placing in a somewhat more current time setting and even using current events. This is the Ultimate universe with Ultimate X-Men and is completely unrelated to the other series.
For the tv cartoon series it started with the special "Pryde of the X-Men", which was only 1 episode of a series never to come. Then you have the 90's series The X-Men (also X-Men TAS), which ran for 5 seasons. In late 2000 started X-Men Evolution, which ran for something over 3 and half seasons (the fourth season was cut short). And in 2009 you had the series Wolverine and the X-Men, which ran regretably for only 1 season leaving with a small cliffhanger.
And then you have about 4 live action movies and another one comming up.
