hmm lets see, Lab: has a nice last boss feel to it. Home: its like leifang/genfu/janlee remix. Other themes reflect the atmosphere of the stages quite well. Whether u like it or not, you will all remember the circus theme and the zack island themes .. lol
flow (top floor), Street (roof top), Fuel (after the explosion) ... all those are quite solid themes. I've used quite a few in my tutorials and they sound quite nice when u crank the volume. i think its the volume settings that make them seem more subtle than what they really are.
also, I know its cheesy as hell .. but in ten years if anyone blasts out "EVERY BODY GOT TO MOVE ON" you know you all will be dancing and singing along with that shit ... lol