Toyayo, mention ur connoisseur c5's and want a receiver to match well. basically, i don't understand why ur looking for a receiver to match these speaks if ur talking about 2 channel music. if ur looking for 2 channel only music for a receiver i would recommend the outlaw rr2150 receiver selling at $599. It is an internet only company at the moment, but it is the bomb. its a 2 channel model however and i will go out on a limb considering the thread at hand and recommend a avr for home theater. First off, i want to describe the speaker a bit beforehand. The connoisseur c5 is a great budget minded floorstander with a lot of expensive technology from their higher end speaks incorporated into them. The tweeter section of these guys is very smooth and unharsh if u will with the tweeter tech stemming from the more expensive veritas line. U get a neutral, open sound while at the same time remaining laidback. these characteristics are very important to examine when deciding on which receiver will match. Although these speaks are good for music, u may need a sub to fill in for the low end. (Rel sub or Velodyne recommended) BTW, good for music will generally make them GREAT for HT, in this case i believe this to be true. They incorporate ur 2 6.5" woofers in which placement will be absolutely critical in 2 channel config since the port is in the front. i would place them anywhere from 2-3 feet from ur back wall as a good starting point. The only other pertinent info that "I" know of w/ this particular speaker is that the sensitivity is around 92-94 db if memory serves me right which will make them pretty easy to drive with a moderately priced receiver, which i believe is the real question at hand.
So, if ur lookin for 2 channel, look toward the outlaw, with a money back 30 day guarantee i believe is what they offer.
But i suspect ur looking for bells and whistles since ur on this particular thread, so in that case i recommend 2 a/v receivers for which i absolutely am confident will do the job well but U NEED TO LISTEN FOR URSELF as audio is very subjective, and therefore is just my opinion based on what i myself hear and like. with those speakers, which in all honesty ive only heard on 2 occassions for very short listening periods as i auditioned them vs B&W which i believe to be a strikingly similar sound to ur speaks, but i liked the B&W sound so my audition was cut short on the connoisseurs.
heres the receivers i would reccomend
Pioneer elite vsx-74TXVI, which is thx select2 receiver with some real gusto and connectivity options to boot. It is moderately priced and has good build quality compared to other moderately priced receivers. It fits the bill in my opinion as it is neutral to warm sounding which should make ur highs sing while not fatiguing ur ears. It would partner well with them speaks.
Denon 3806
I like the denon sound with my B&W and ur connoisseurs are close in sound to the B&W in my opinion. Like the pioneer, it has good connectivity, hdmi, etc.. no thx select or other thx certification, but imo, this is not important. I like the 2 channel sound of the denon better in an A/B comparison.
Bottom line, listen to these two receivers or if ur going 2 channel just order the Outlaw as i know u will love the sound. Sorry for long post, just want to point u in a clear direction i hope this helps.
-Jeff