If you really want to save a lot of money, and you're doing this only for movies - here are some more thoughts:
The B&K AVP3090 is a steal on the used market at <$300, and somtimes close to $200. It sounds great and is reasonably quiet, although may be suseptible to RFI that requires special attention. You can probably get a Ref 20 for under $500, and Ref 30 maybe for a tad more than $500 depending on condition/age. B&K service and support is the best I've experienced from any company. The 3090 doesn't have optical in, but does support DD and DTS.
I don't have experience with the Rotel 1068, but do with other Rotel pre's and it's been good. They're not bullet-proof like B&K, but they are built nicely, and sound great.
The Sherwood-Newcastle AVP9080r can be had for $200 and is quiet. Setup isn't as user friendly or flexible as the B&K nor the Lexicon DC-1. One strength is it has 5.1 inputs.
I tried several Yamaha receivers before finally going to a separate pre/pro, and amp. Don't waste your time and money on them.
I'm not sure if this is a fair comparison, but I had the Acurus Act 1, which is pro-logic only, and while for the money it was nice, it was very noisy and prone to ground loop. It's also a bit bright. I don't know of these traits are common to the Act 3.
Back to the Lexicon DC-1, I went throuh all of the above, still have the 3090, and the Sherwood, and the DCs is my primary HT processor. I frankly can't relate to the comments made above. The sound quality rivals many pure stereo pre's I've tried, including Rotel RC1070, and also Classe CP35. It has its shortcomings, but I really like the flexibility (7.1 capability) 7.1 inputs, Coax and Optical ins (though only 2 of each), and easy, flexible setup. My use is PRIMARILY music videos in a dedicated home theater, so the music quality is important to me. I generally watch movies upstairs in a less critical environment (ie the family room) using the B&K as a pre-pro.
Finally, since you're talking about used here - I'm sure it's not gotten by you that you can buy one, if you dont like it resell it and move on to the next one.
