Power amp for monitors.

Those spec 90db sensitivity, so by that I would think you wouldn't need a lot of power, but power is cheap and with passive monitors I've always found it better to use at least 2x the power rating of the monitor to ensure that your transients are reproduced well.

I'm telling you, I LOVE the Emotiva stuff. I absolutely don't get paid by them - just love their products for the price and quality. I bought the XPA-1L Mono Blocks and freaking love them. They just came out with the XPR-1's - which at 1000 W Mono would be monstrous - for $1500 ea. But - the XPA-1L's you can get for around $1000 for the pair - a third of a Bryston. Also - check out Ebay - they're are usually just smoking deals on Emotiva amps on there.

Maybe littlesicily can chime in...He's tried a bunch...

I have the ProAc's and tried the following amps:
Bryston 4BST - loved it and after going thru all the rest landed back here.
McIntosh MC2100 - smooth but bass shy and not as punchy as Bryston
Hafler somnthing - ehh
Yamaha (the one they made for the NS10's) - lots of power but not as enjoyable to listen too. Functional.
Emotiva... same ones John has plus another lower line one - These were my 2nd choice...as he described, really great imaging, depth, etc. Just a little bright in my room.

Hey Dan, any amp recommendations?  

There's a number of single space rack amps available.

www.proacousticsusa.com/products.php?sId=1095

OK,
some names to pass around for good power amps, too....

Adcom.
Definitely well worth a look especially if pricing matters. Solid sound, i like them very much. Great bang for the buck. Based on Nelson Pass designs (and these are excellent).

For european buyers...

Restek. German high end. Mono blocks and versions with balanced XLR in available. I recommend demoing before buying. I did not like them all the same, and found we had slightly differing results depending on the feeding DAC, so there might be something picky with impedances somehow. But - this is criticism at the highest level, great and solid amps.

Array Audio (formerly Van Den Hul amps). 4-5k-ish amps from the Netherlands that i was highly impressed by. Damn fast amps with very high dampening factors. Not cheap, though...

I listen to these amps regularly...

For those very low on cash and in need for an amp, or as a backup:
Slightly modded, even Alesis and Behringer rack amps can make fairly good studio amplifiers. There are quite some mods described on the net, and they are dead cheap new.
One can find e.g. some of the Alesis amps (A-500/300? of whatever they are called) even cheaper second hand with problems like intermittendly failing channels or channels with different volumes, all kind of probs similar. I found *mostly* it is a very simple and quite common problem - cheap pots (that should be bridged anyway and used a monitor controller instead) and relays, that fail or show signs of beeing near their end of life, worn out, making bad contact. Very easy, fast and cheap to repair...
You might not want to hear this in a gear forum like this, but - by design - they are not half as bad as one would think - stock. High bang-for-the-buck factor...