hmm usually hard surface floors are better because they reflect all the bass instead of absorbing it (plush carpet is terrible).
i've never used my pro's at home, but when i had my acs48's, no matter where i put them in my room, the bass would be boomy and not very loud, even at high volume. however directly above my room (in the kitchen) it sounded even louder (not counting that most of the sound got absorbed in the ceiling). this sucked because i couldn't have loud bass without bothering the whole house. my room is a small cube shape with plush carpet, btw.
my dorm room is a whole nother story now. its slightly larger then my room (heh). we have a flat crappy carpet (my roomie's hehe), but it doesn't cover the whole floor. my sub is directly on the floor (no carpet). also, my desk is sort of enclosed. where my sub and puter are, it is enclosed on all sides except the front obviously. 2 of the walls are concrete cinder blocks and the third is a hard wood surface. here, the sub is punchy and powerful, but it dissappates rapidly. this is a good thing, because even when really loud it doesn't carry through to the neighboor's too badly.