Integrate 2-channel or go all 5 channel


I'm at a crossroad and could use some advice. I'm looking to integrate a 2-channel into my HT environment. I have ~ $4K to spend and cannot decide whether to drop all of it on a modest 5.1 pre/pro and amp combo and retire the receiver, or integrate a 2-channel into the mix. Would I get significantly better sound from a 2-channel setup integrated into my existing environment? If I went 2-channel, I think I could do it for about half my budget. Today, I'm leaning towards the 2-channel. My preferred amp would be a McCormack DNA ??. I'm looking for recommendations for a pre-amp. The requirements are, HT passthrough, and a remote. I have 2-way monitors and want to keep my sub in the 2-channel mix. Does anyone make a 2.1 pre-amp? I also need some way to set the frequency cutoff between to mains and the sub.
Based on the need to use my sub, next week I'll probably be leaning towards all 5 channel gear, amp there probably would be a Bryston.
There are a couple questions buried in the above diatribe. I sure could use some guidance.

Existing equip:
Yamaha RXV-995 receiver
Vienna Acoustics Haydn mains
Denon DVD-1600 DVD/CD/DVD-A player
M&K MX-150 sub.

My musical tastes are mainly rock & roll, if you think Pearl Jam, that should give you a good idea. and techno(house mainly).

Thanks in advance
snipes
Look at a USed Anthem AVM-2 and the Anthem MCA-5
Great combo and you will have money left over.
Well I don't have the experience of these other guys, but I'm in your same boat (except without the sub). Most audiophiles it seems will push the 2 channel system above all else, and I'm sort of leaning that way. A great point someone on here made to me was that you are not as picky with the sound in your home theater because you are also watching the screen, whereas for audio that's all you've got.

So I'm thinking (for me) get a separate amp/pre or integrated and bypass my receiver for music, and then passthru the same integrated for 2 channel during movies (powering center and rears through receiver). The other option I am considering is a 3 channel amp, which adds the difference that the center will get good power, even if the receiver's pre-amplification for the center isn't ideal.

Hope this helps somehow. Good luck.