The things that I recommend that you look at when shopping are: connections (does it have everything that you want/need), auto calibration (a huge plus, IMO), features (can it do everything that you want), power (can it play as loud as you want and still sound good), ease of use, and the remote control. Price, of course, also weighs into it - I never want to spend more than I have to in order to get what I want, but I don't want to spend less and then be unhappy for years because I bought something that doesn't do what I want.
My last two receivers have been Pioneers, and I'm happy with Pioneer's MCACC auto calibration system. I recently got the chance to try out Audyssey on the
Denon AVR-E400,
Onkyo TX-NR626, and Marantz NR1504 receivers. Audyssey does at least as good of a job as MCACC, but the limitation is that you can only store one configuration for it (MCACC lets you stores up to six different configurations for six different listening positions). Because I have two listening positions that are significantly different in terms of where they are located in relation to the speakers, MCACC is a better fit for me.
I'd suggest also checking out the Pioneer VSX-1123 (I've seen it as low as $430 on sale at Newegg), and last year's Pioneer SC-1222 (which was $480 last weekend on Newegg), as you do your shopping. For this year's crop, the VSX-1123 offers very similar power ratings (90W/channel) as others in its price class and has the same or better connectivity. For Audyssey receivers, the Onkyo 626 offers the most features and connections for the money (that I've seen), but Onkyo has taken a hit in reputation due to reliability concerns in the past few years - however, they did add a fan to the 626 which should help reduce overheating issues. The Denon AVR-E400 is a solid unit, but I don't think it's a great value compared to others out there, including other Denons.
