My girlfriend and I just moved into a new home, and I get to upgrade my system! I'm looking to pick up the new Panasonic TC-P55VT50 plasma, Oppo BDP-93 Blu-ray player, and the RSL 5.1 speakers. Now, I need to choose an A/V receiver to get the best out of the equipment listed above. For reference, I'm looking at the Marantz SR7005 or the Anthem MRX 500 or 700. I want something that will give the best audio and video quality; I don't care about the extra crap I won't use anyway. If any of these would be perfect, or you can think of any other great solutions (even separates), I would really like your opinion.
Congrats on the move and the opportunity to upgrade your system! We haven't reviewed the VT50 yet, but Tom Norton just finished his review of the less-expensive ST50, giving it Top Picks status. (That review will be in the July 2012 issue of Home Theater magazine.) And last year's VT30 was excellent, so I'd say the VT50 is a safe bet. Without doubt, the Oppo BDP-93 (reviewed here) and RSL 5.1 speaker system (reviewed here) are both superb choices.
As for the AVR, I think you can't go wrong with any of the models you mention. We reviewed the Marantz SR7005 here and the Anthem MRX 700 here, but we haven't reviewed the MRX 500, though I would expect it to be similar to the 700 in most respects. (The 700 is rated at 120 watts per channel, while the 500 is rated at 100Wpc; both have seven channels of amplification.)
The Marantz uses Audyssey MultEQ XT room correction, while the Anthems use the company's proprietary Anthem Room Correction (ARC). Both are highly regarded, though I think ARC would get the nod from many listeners. In our measurements, the Marantz handily beat the Anthem in terms of power outputespecially with seven channels driveneven though they are rated nearly the same (125Wpc versus 120Wpc, two channels driven into 8 ohms). The RSLs are rated to handle 25 to 125W, so the Marantz might be a better match for them in this regard.
Video-wise, the Marantz edged out the Anthem, passing the analog video-clipping and luma-resolution tests, which the Anthem failed and got a borderline score on, respectively. (We don't recommend the Anthem if you plan to convert analog video sources to HDMI.) Both got a borderline score on the digital chroma-resolution test and failed the analog chroma-resolution test, and they both passed all other video tests.
You say you don't care about "the extra crap I won't use anyway." I'm not sure what you consider "extra crap," but the At A Glance points for the Anthem include this one: "Light on bells and whistles, heavy on high-end sound." On the other hand, as discussed above, the Marantz wins a head-to-head comparison in most respects, and it's $400 less expensive.
The only other AVR I might recommend in a similar price range is the Pioneer Elite SC-57 ($2100, reviewed here). Our measurements indicate it delivers more power than the Marantzthough not too much for your speakersand it passes all video-processing tests except standard-definition 2:2 and chroma resolution when converting component to HDMI.
In the end, it comes down to personal taste, which I can't advise you about. If possible, try to listen to each of these with the same speakersideally, the RSLsto find the one that sounds best to your ears. As I said earlier, I think you can't go wrong with any of them.
If you have an A/V question, please send it to firstname.lastname@example.org.