I think I've said it on another thread but yes, Spectacular Spider-Man is the absolute BEST Spidey cartoon EVER released IMO. I have seen them all and this knocks each one of them out of the water.
Haven't seen the Hulk movies yet but surely will soon. Ditto Next Avengers, from which I've heard nothing but praise. And personally, I thought both Superman/Doomsday and Batman: Gotham Knight sucked. The first one didn't live up to the movie name as it turned into another Luthor confrontation, and the second one just plain bored me with all the different animation and underwhelming stories.
Regarding the Ultimate Avengers movies, I thought they were merely passable. As to why they didn't just adapt the Ultimates comic storylines, I'm guessing they're saving that for the live action movie? At least that's what I heard.