I agree with Lepkron...
I have a Denon 3805 which claims to be 120x7. I doubt that rating is accurate with all 7 channels driven....90-100 is probably more accurate.
Anyway I originally had three 4 ohm speakers (Polk LSi's) and two 8 ohm
surrounds on them in a medium/large room (22x16) and the 3805 did an adequate job, but not overwhelming.
I added a Denon POA-2400 amp (200x2) just to power the two fronts and WOW what a difference. Plus there's now less strain on the 3805 which probably allows more current to get to the center and surrounds and the LSi15's are singing during 2 channel mode.
For just $300-400 you can find a similiar amp(Parasound, Rotel, Adcom, B&K, etc.) used on Ebay and make a big difference to your system. I hear Outlaw Amps are supposed to be pretty good as well but I've never heard them.