This could turn into a very long response..but I will try to keep it on point.
My experience with receivers is that some of them Taylor frequency response to be saleable. I walked into a Circuit City looking at some mid priced stereo receivers for the lounge area. After confirming all of them was set to the "Flat" setting; ie/ No bass or treble boost, no loudness countour selected, no extra bass buttons on, and no subwoofers powered up in the listening area, I was amazed at the difference each one had sonically..at the same perceived volume level from the same set of loudspeakers. The length of wire from the receivers to the speakers was uniform so I was not hearing an "extra roll" of wire somewhere.
This simply means that the use of a stereo receiver may not be an accurate tool...as the preamp section in the receiver is coloring the sound.
Consumer gear is designed to work with consumer gear.
Have you noticed your bass is rather thin on other systems?
Possibly because bass is inaccurately boosted in the receivers per-amp stage to make them stick out in auditioning for saleability. I especially noticed a rise in the bottom and highs of the Sony receivers I was checking out but the Denon and Onkyo receivers sounded pretty neutral. I was familar with the acoustic setting and the loudspeakers so their was no excuse for the Sony to have that much contour at the flat setting.
This brings me around to the preamp. Your console has a preamp in it and you are powering another preamp in the receiver...possibly causing an impedance mixmatch...and that will color the sound as well.
When using a power amp..you may notice first off that the bass is not what it was with the receiver. This is a good thing as you are now hearing the sound as uncolored as possible due to correct impedance matching between your board, DAW, or othwer source that is already preamped, and intended to go into a power amp.
You can get use to the translation from a receiver but still I warn against using a receiver unless it has preamp out/poweramp in jacks and can be electrically separated.
Now the question at hand.
Their are many gear poweramps out there from Hafler...all the way down to some rather inexpensive units..your budget will have to be the deciding factor. I actually use a high end vacuum tube stereo amplifier for my mixdown use and one for mastering. Althouse these have been noted for coloring the sound, the lack of odd order harmonic distortion is just the key for those long 14 to 16 hour days where I am continuiously behind the console. Tube amps are expensive...some are in the mid $20,000 range for wattages in the 30 to 50 watt range but lower priced units are out there. I actually have an alesis RA100 laying around as an emergency reserve and have no problem recommending a Crown, QSC, Crest, or other good rugged power amp.
YMMV (your mileage may vary)of course and their will be no problem selecting an amp of 100 to 150 watts/channel for your speakers as clean power is so much better (solid state amps) in the long term to keep from clipping and burning out your loudspeakers from underpowering them.
I also advacate some fuse protection for your speakers in the 2 amp range until you get to know your amp. Better safe than sorry.
Another really nice monitoring amp that I highly recommend is the Rotel RB1050. It is 70 watts/side, has clip indicators, sounds super natural, runs cool and has separate left /right gain controls. Retails under 500 dollars. A winner for the money.