Resident Evil rules over all other survival horrors. It has an almost believable story, which is nice. See, the zombies and monsters aren't magical creatures from some other dimension, they're genetically engineered bio-weapons.

And while the games are similar, Capcom always do something a little different with them (RE2's scenarios, RE3's random-ness, nemmy, lots of stuff in CV/X) which is cool. And all the games are great, there isn't a "bad one" (or an RE version of FF8, which lots of people hated), at least as far as I know*. The only one in the series I have a problem with is Zero. Two characters at once took away a lot of the scare-factor, but it was something new at least.

Also the best Resident Evil game = Code Veronica best puzzles and it is also the most non-linear RE game yet.
Nah, REmake beats them all hands down. You're alone(pretty much) in a creature infested mansion with just a Handgun and you're wits. And the whole Crimson thing added tension because you had to dodge most zombies rather then filling them with horrific amounts of lead. Dodging does get a little annoying at times, but it means that a lot of areas generally aren't safe or clear, which means you always have to be careful wherever you are. But CV:X is a very good game.

* Survivor and Gaiden don't count! They never happened!!!