Comparing Resident Evil 4 to Halo based on single player... You smoke crack right? Neither Halo was ment to have an amazing single player, it was like a bonus that you had some thing to do for practice. I would like to see Resident Evil turn every jock in the nation into a gamer like the Halos did, oh wait no multi-player!
I would say the first Halo did have an excellent single player, with a great, immersive story, etc. It was at least a 20-25 hour single player game, which is quite good for a FPS- compare that to something like Rainbow 6, Timesplitters, or Counter Strike, which had stupid single players just for practice. Halo 2's story was far worse and far shorter than Halo 1's, which is why I think RE4 beats it for single player. I played Halo 2 on online multiplayer and it was great- where the game shines, but Halo 1 is the game that had great single player and no online multiplayer. Anyway, I was dissapointed with Halo2, but I'm a real gamer- I care about story, art direction, innovative gameplay, etc. Bungie may not care about me, but I still think they dropped the ball on Halo 2's single player, especially compared to the excellent single player of Halo 1, which was very good, though derivative of half-life.
Maxcast- MKDD rocks- super fun game!