Need more volume, cheap. Any advice?

Just had installed three pairs of Klipsch 5800-CDT-C ceiling speakers in three different rooms and got a two-zone Denon receiver (AVR 1910, 90 wpc). The kitchen and living room are on one zone, using 5 channel stereo, and the tv room is zone 2. These are the only speakers in my setup. The problem is I was hoping for deafening volume when needed (rock and dance) in the LR/Kitchen and can only get close to that when I turn the receiver to 100%. So, I was thinking of changing the LR/Kitchen to zone 2 because I can send the zone 2 output to a second amplifier. I don't need perfect sound, but don't want distortion and don't want to blow the speakers. Can anyone recommend a four channel amp that would provide more/better power than the Denon receiver? Something I could easily get used for $300-500 would be perfect, if such a thing exists. Though not ideal, I could also probably get rid of the Denon and start over, but would still need inputs for TV, ipod, DVD, etc. Much appreciated.
you definitely need an external amp--with all channels driven your denon ain't putting out anywhere close to its rated power. i saw some b&k, emotiva and adcom 5ch amps listed on these pages within your price target--any of these will suit you fine.
Thanks, Loomisjohnson. Even when I only run one pair of speakers at a time, it's not loud enough. With the brands you mentioned, how many watts per channel do you think is enough?
Like Spinal need an amp that goes to 11!!!
You might but you don't "definitely need an external amp." You may need more gain, not more power. If you get an external amp that is capable of producing more power but has lower gain you'll end up with less volume, not more.

If you have it all the way up and it's not clipping you need more gain or more efficient speakers.Unless you can find out what the gain of the amp is in your receiver you have no way to determine if a given amp will have more gain unless you just try it.
I'll see if I can find the gain rating of the Denon and compare it to the ratings of the others. I think the Klipsch speakers are efficient, 94 dB. At least higher than anything else in the category. Thanks for the response.