OK, so I have all the direct to DVD Marvel movies, and they are great!
Ultimate Avengers starts things off with a bang, by covering volume 1 of the Ultimates graphic novel. They did leave some of the more graphic elements out, but overall it was a great pic. Aliens are invading, and after finding a frozen Captain America, Nick Fury (who resembles some one who hates snakes on his plane) assembles the Avengers. They are Thor (Who no one beleives is a god), Hank Pym (Brilliant scientist, but ego the size of texas), Janet Pym (a mutant in this one), Hawkeye and Blackwidow (Sheild agents promoted from undercover ops to work with the big boys), IronMan (Billionaire playboy and all around jerk, Tony Stark) and The Hulk (Bruce Banner is a S.H.E.I.L.D. scientist working with the supersoldier formula...that's the basis of this Hulks powers)
Ultimate Avengers 2 takes us to Wakanda and introduces an 'ultimate' version of Black Panther. This is where we see the team start to gel into a more coheasive (sp?) unit. This DVD wraps up the Alien Invasion story line.
Invincible IronMan, out of continuity with the Avengers movies, this tells the tale of Tony's growing up and accepting the responsibility of the IronMan armour. Add Chinese mythology and The Manderin, and you've got a rollickin' movie that I hope will be better when it comes to live action next year.
Doctor Strange, Classic take on Doc Strange, starts with him as a brilliant, but arrogant doctor who loses the use of his hands in a car accident. Wong eventually offers him the use of his hands back, at the cost of training with the Ancient One. Very good take on a classice character here.
If you are a fan of Marvel Comics, I recommend all of these.