I have good mini-monitors in both the main and HT system, so I chose the second option. But I have also had speakers with good bass down to 30 Hz and have used a sub with one of those, too. The disadvantage with mini-monitors is that they won't play as loudly as many larger speakers, but then, ours will play plenty loud enough for us.

One can put the main speakers where they sound the best and put the subwoofer where the bass response is most even, and these are seldom the same place. As well, with the crossover, one can notch out the highest room resonance, which is about 70 hz for an 8 foot ceiling (565/8 = 70.6). I have never had that much difficulty in integrating subs and sats either at home or in a store.

Also, very few speakers can match the extension and output of even a good mid-priced sub.