Originally Posted by Trojita
In all honesty you are going to hear all sort of suggestions for receivers that are based on personal preference and the receiver a person owns.
I personally own a pioneer and like it. A lot of people swear by Denon. The watts generally aren't that important since some companies might just fudge those numbers.
The rule of thumb I have always heard is that you should only spend less than half of your budget on speakers, on a receiver. This is because receiver technology outpaces speaker technology in growth and Speaker quality will effect your sound quality a lot more than the receiver (Not to say that it doesn't).
Some brands to look for
Onkyo- They seem to have the best bang for your buck especially with entry level models, but I heard they get real hot. This may or may not effect you.
Another good forum to go to would be avsforum. The guys there know a lot about what they are talking about.
Hate to say this, but a terrible question to ask, because it is difficult to answer. You will get only opinions from people. And that's all they are opinions. Receivers (and speakers for that matter) tend to be a personal choice, which I'll try to explain below.
Ah!..yes.. AVSForum, I haunt that forum too. Between there and here, I wonder when I sleep... But unfortunately, you will get all the same type of fanboy hype there also. Like Trojita, I have a preference for a brand also... I like Denon. That is not to say that there is anything wrong with Pioneer. All of the brands listed above are good products. I would throw a couple of additional manufacturers into the mix: Yamaha, and Sony with their midrange products. (stay away from Sony's real low end stuff)
As Trojita stated, don't believe what you see regarding Watts/channel. These numbers are always overstated by the Manufacturer, and should not be the only criteria in your selection. There is only one exception to this rule: harmon/hardon; harmon/kardon actually provides the proper spec for their receivers, and their W/channel reflect this. The spec always looks low when compared to other manufacturers.
The best way to determine which receiver is best for you, is to get out and listen to different receivers. It is often difficult to pair up the exact speakers you have to a certain receiver, but if you can audition different receivers though the same speakers, you will get a feeling for your brand preference.
The reason I mention brand preference is that different manufacturer's receivers sound different. For example, my preference: Denon, Denon's sound is a very warm mid-range, the high frequencies, are not overdriven as to cause, what I feel to be over-accentuated high frequencies, like a Yamaha would have. Not saying Yamaha is bad, hey I recommended including it in your list. Many swear by Yamaha, as they like the high frequencies, I personally find them fatiguing, over long listening sessions. Nothing wrong with it, just not my taste.
Also Trojita's choice of Pioneer, great product, similar sound to my preference, although slightly more high frequency reproduction.
If you can't audition receivers locally, and intend to look on the internet, find someplace that has a liberal return policy, so that if something doesn't sound "right" to you, you have the option to try something else.
You didn't mention your budget, so I assume your speaker selection is a good one, those speakers are ok, for the price you are going to pay for them. Follow Trojita's advice, spend the bulk of your budget on speakers… You will have them much longer than the technology that will eventually drive them.
Because you mentioned 5.1... moving to the Polk Monitor 50 tower speakers, start to save your money for your next purchase. You are going to need a decent subwoofer. You will find the M50's lacking a little, in the low end. Assuming your set-up will be used for watching movies, the purchase after that would be a center channel speaker. This purchase will be important, because you want this speaker to me matched to your right and left front speakers. You will end up needing another Polk speaker for this duty, as a center speaker matched to the L/R will give you a seamless front soundstage.
As an example, this means nothing more than when listening to and watching something, when a specific sound moves from the extreme right to the extreme left of the front sound field, the center channel (in this case a blend of the R/L) doesn't change the characteristics of the sound, and make the center channel "jump out" at you. The sound movement should be a nice smooth pan across the front three speakers. A different brand center will contain different drivers, that will sound different from the R/L front speakers. This will change the smooth pan that should occur, to what apears to be sounds that "jump" from one speaker to the next.