I've done a Resident Evil DVD Marathon replete with special features and most of the commentaries. The third one (Extinction) directed by Russell Mulchay is the best of the bunch I think and book ends the trilogy nicely. Except that's not a trilogy. The follow up (Afterlife) is great and does kind of fit with the first three. Retribution, however, is just nuts. In a good way, but it doesn't really seem to "fit" as well as the other films. Of them all, though, its the most like a video game.
I thought I'd actually enjoy these films less than I did - but the reverse is true - I love them even more. I have never played the games so I'm not full of butt-hurt that such and such didn't appear or had the wrong coloured hair or whatever. And honestly - the film of the game is never going to be as good as the film of the game you had in your head.
I've embraced the madness.