PreAmp for HT

Yes, if dedicated HT set up, then probably Lexicon. If mostly music, with some movies, then the Classe or Proceed are going to be close toss ups!
The Lex has features galor, which make setting up 5 or more "less than ideal" placed speakers very "EQ'able", "tweeekable", and adjustment friendly! Also, of course, 7 channel logic, more tweeks, etc. I consider the Lexicons more of a "digital only" (not Analog) kind of a preamp/processor. It's a great dedicated movie piece, but not as "straight-analog 2 channel" pure!!!!...the Classe and Proceed do this better to nit pick in my experience! I've also have extensive experience with the Classe with the B&W's, and very much like the sonics from this combo for both HT/music!
However, Using something like the Lexicon (which I've also deal with extensively) allows you to do things to your speaker set-up that's very very critical for the majority of HT set-ups out there in my oppiion. The Advanced bass mangment on the lex let's you perfectly dial in the right crossovers for the channels! Uusally 80hz "small" is too high for most speakers, and "large" full range is not acceptable for most, even full range" monitors for HT dubties!!!(speakers can't handle it really..unless they have big powered woofers built in.) The Lex let's you select different crossovers, as well as has advanced EQ's and paramaters, the others don't have! In short, it's a much more THX dubbing studio Quality piece for doing movie tracks in a home environment.
Another selection to consider, for only 5 channel dubties (although I heard through a source, there releasing a new model), the ARAGON SOUNDSTAGE has the flexibility almost of the Lex, with the audiophile sonics of a high end preamp!..just something else to consider for less money as well!
So, yeah, you should specify you're needs with the preamp.
Good luck...

I own the MC-12 and do both movies and music extensively through it. You won't go wrong with the MC-12, IMO, though you can probably get by for less money depending on your needs. If you're doing exclusive HT, I'd buy one of the used Lexicon MC-1's (for a LOT less) - it's tremendous on movies. The Bryston SP-1 is widely regarded as being music friendly and I believe it's considerably cheaper as well.

I don't think it's accurate that Bryston builds all Lexicon products. I know Lexicon amps are just rebranded Bryston product, but I didn't think that Bryston built the pre/pros for Lexicon. It could be that I just learned something today :-)

Bryston used to build amps for Lexicon, not anymore and for sure they don't build the Lexicon pre-amps.

Bryston only builds the NT series amps for lexicon. The new amps (LX) are built by crown. Lexicon builds their own processors in conjuntion with Harmon.

What about the recent EAD Theatermaster Signature-8? Exquiste sound quality for 2-channel as well as HT, analog pass thorugh for your SACD or DVD-Audio, many multiple HT modes include 7.1, a great crossover, upgradeability, a womderful DAC section, and compared to some of the units you mentioned a very good value.