Resident Evil 4 is a masterpiece of videogame design. I place it alongside Metroid Prime as the greatest videogame experience of this console generation.
Playing through the game there is the constant feeling that the designers thought carefully about each and every element; not just one aspect of it, but really contemplated each element from several angles: is this functional? is this neeeded? is this cool? does this fit with the characters? does this contribute to the atmosphere? is this fun?
The hallmark of such a good game is that its individual elements meld into one cohesive whole, far greater than "that one cool sequence" or "that awesome boss." Resident Evil 4 is truly amazing.
One caveat, though: I almost wouldn't put this in the same genre as the other Resident Evils. To me, it wasn't nearly as scary or suspenseful, because I almost always knew what was coming and I was confident I could handle it. Of course, if lousy control is a requirement for epic scares, maybe we should just let them go.