First off, most probably haven't heard of The Warriors: The Game, based on the 1979 cult classic, for the PS2. Good graphics, great friendly AI, and a hub world where you can steal things, accept side missions, or just pound on people with your crew. There's also the fact that the gameplay is actually fun!
I'd also like to nominate three Lord of The Rings games that were movie-based. The first is The Two Towers, generally good hack and slash fun where you can choose between Aragorn, Legolas, or Gimli. The second is The Return of the King; the story branches between Aragorn's group, Gandalf, and Frodo and Sam; with a bit fo variation in gameplay between the three. There's also co-op, generally fun with a friend. The third is the Battle For Middle Earth, essentially the events of the films in RTS form; has different styles of play for Rohan, Gondor, Isengard, and Mordor; and it's really fun to play the battle of Helm's Deep and Minas Tirith from an RTS perspective...and perhaps change history by saving Boromir.
Three Harry Potter games have my affections; Chamber of Secrets, Prisoner of Azkaban, and the Quidditch World Cup. Chamber of Secrets has decent gameplay, as well as a free roaming Hogwarts; but Prisoner of Azkaban beats it on both accounts. Quidditch World Cup is great if I ever need a dose of Quidditch...
Another that I happen to enjoy, or at the very least parts of it; is Star Wars: Episode III. I might be one of the only ones who enjoys fighting the Jedi as Anakin, and fighting Clone Assassins as Obi-Wan Kenobi. The game play is fluid, least in my opinion, and it's always fun to duel friends when it comes to Anakin versus Vader...and have Vader win.
The Matrix: Path of Neo, is also an enjoyable romp. For one, it's The Matrix. For two, you're playing as Neo. For three, it's MUCH BETTER than Enter The Matrix, where you practically NEEDED cheats to pass a helicopter fight. You can also kick the ever living crap out of Agents with little difficulty at a later time; hint, it involves bullets, and sending them back...
To me, Reign of Fire is good...on the Dragon levels where you have backup. Unfortunately, sometimes the game gives you shit for allies on either side, but for the most part they're reliable.