Alien vs. Predator 2 scared the crap out of me before I completed it, and it still does sometimes. Some serious heart-rate going on. It's a very well-balanced game in terms of the differences between the three races. And the levels tie in with each other. Reminds me of Starcraft. The Marines would be the Terran, the Aliens would be Zerg, and the Predators would be Protoss.

And on the subject of which Street Fighter games I like - pretty much all of them (although the voice-overs in Super Street Fighter really annoyed me). But my FAVOURITES are Street Fighter Alpha/Zero 2 & 3, and Capcom vs. SNK 2.