Suggestions for an affordable pre/pro

Yeah, from what you're saying, I'm gunna agree with the Acurus Act 3 choice. I've owned 4 of these over the years (don't ask why I sold em...it's complicated -lol). I've also had Macintosh pieces, Aragon Soundstage, "updraded" Act 3, Sony's 9ES pre, and the Krell 5.1 HTS. And, even though other more expensive pre's are "quieter" (you mentioned hiss - which the act 3 has a bit higher noise floor than others, but not manageable, IMO - and I've had 'em in small, quite rooms) for the money, the sound is powerful, clear, detailed, dynamic, and pretty musical! There's better, yes. But, for much more. And, for your needs, I think it might be a good fit.
But, you sound like you might be a bit more finnicky than some. In which case, your tastes/priorities will vary.
The Krell HTS, is as clean, detailed (for 20bit), and refined as ANY 5.1 pre'pro you'll ever find, period! Although there's NOTHING more dynamic than the Act 3!!!!
The modified version is a lot more (if you can find one, which I've owned) - which is richer sounding, more detailed, and just as dynamic! But, for like $300 range, you can get very acceptable (MUCH more dynamic, uncolored, nicely detailed digital 20bit sound).
System dependency always matters though. So tastes and systems might vary.
As for NAD, I'd check quality control, otherwise nice sounding, overall. The Rotel is dynamic, slightly recessed on top, a tad bland, but otherwise descent enough sounding.
The Anthem is descent, but I think it sounds a bit like the B&K, kinda warmish, not as dynamic, but fairly good balance, I think. The inteegra?..no experience.
The marantz AV9000, I've sold and installed before. It's, like the Rotel - descent.
What you won't get with these pre's are the new DSP room correction however. And, knowing nothing of your room, that could be very useful, so consider. In a perfect acoustical space, you wouldn't bother.

Hum. Don't know why the last post posted 2x's. Oh well.
Actually (and I've owned the Act 3,Upgraded Act 3, Aragon Soundstage, Krell HTS 5.1, Macintosh MX130 THX, Classe SSP25, and others), even though I've had and experienced "more refined" pre'pro's than the modest Acurus Act 3, I WOULDN'T HESITATE TO GET ANTHER ONE FOR A SYSTEM (OR FRIENDS) IN A HEART BEAT!!! It's just a darn good, amazing little 5.1 DD/DTS pre/pro! Clean, clear, uncolored, SUPER DYNAMIC, good soundstage, etc!!! (of course, digital connection is the only way to go on that unit, as it's all digital).
Hope that helps. Heck, I'm excited about that little unit right now, just thinking about it! (and that say's something).
(Also, why did I sell them before, if they were so darn good, you ask? Well because I got offered more for them than I paid! -money making comes first, ya know. Also, I had to try others to compare. So I traded)

Used to have an Outlaw Model 990 that I sold and replaced it with a Pioneer Elite VSX-74TXVi receiver that I use as a preamp/processor. Purchased mine a couple of months ago from Hi-Fi Heaven for $500 new. They had quite a few available in stock. You could use the built-in amps (140w/channel) that would have a better chance to keep up with your other components. Good luck with your search.

Thank you all for your responses. There's no substitute for the experience of guys with good ears.

Bdgregory, I wasn't even aware that the Lexicon included a preamp until you suggested it. It's an intriguing possibility if I'm up to the setup and tweaking it would probably require. Lokie & Slbenz, I was starting to lean in the direction of an AVR until I won that eBay auction for the Adcom GFA-2535 power amp... now that I have amplifiers for all channels I think I'll go the pre/pro route. Javachip, thanks for giving props to my GFA-555 two-channel. It certainly is audiophile equipment to me. In fact, it's what introduced me to how good music can sound with adequate headroom. Kkm & Flrnlamb, you suggested the Acurus Act 3, which I hadn't considered because I wasn't aware of it. Based on your descriptions of it, that may be just the piece I'm looking for.
What's the story with Aragon Soundstage? I couldn't find as much information on it as I did on the others. Was it a short-lived product?

what do you mean, what's the question on the Soundstage? It's a nice enough unit. Good resolution and details, good body and refinement (much more detail than the classe SSp25...much less digital sounding than Lexicon stuff) But it was not quite as dynamic as the Act 3! That's why I went with my ACT 3's. The SS was smoother, and a tad more refined mid/high, with much better signal to noise than the act 3, yes (but the act 3 was liveable in the "speaker his" department, that I never noticed it at normal listening distances mostly (basically, my room wasn't DEAD QUIET). But the Act 3 was more neutral in coloration (slightly cool sounding, with a bit of a a dry grain on top, comparatively). But, mated with the right combo, it was simply terrific for the money! (sytem matching is always key with gear! - so remember.
For $300-400 range, you're simply going to be hard pressed to beat the act 3 for DD/DTS digital movie sound for the money, for certain! PCM digital connection is also pretty decent and musical, with excellent dynamics and good clarity. Better dac's are indeed better rez and body on a good speaker system, yes. But it's all tradeoffs. And basically, I just liked the ACT3 as an affordable unit, personally.
The only reason I let the very rare factory upgraded Act 3 go, is I wasn't using a system for a long time. I also wanted to see what newer technology was going to come up with for DSP room correction, DD HD/DTS Master, and such. Otherwise, that unit was simply a world beater for dd/dts, 24 bit music, and direct analog sources!!
Good luck