Best 2 ch. Amp, for music, under $1k used

My current system consists of:
Classe ssp 25 pre-amp
Musical fidelity v-dac2 with Pangea p-100
Adcom gfa 545
Denon DVD 2900 used to play cd's
Paradigm studio 10 (planned future upgrade to studio 20's)

My question is: what amp would you recommend for my setup? I'm looking for better sound (fuller bass, better imaging, more power for higher volumes and more headroom etc). I'd like to keep it around $1,000, new or used.
By the way, there is a lexicon nt-312 for sale locally for $850. This amp is supposed to be the same as a Bryston 5b-st. Any input is greatly appreciated!
The McCormack DNA 0.5 is a great recommendation. Another amp to give strong consideration to is the McIntosh MC7100 (later version with XLR inputs).

I've recently had the McCormack 0.5 Rev B, McCormack HT-1 Fully Modded (i forget the exact designation), and the McIntosh MC7100 in my system - ended up keeping the McIntosh.

These amps were bought to drive some additional channels, but I recently moved the McIntosh 7100 to drive my mains while my primary amps were out getting serviced and they are VERY good. Far better than I was expecting.

So much of this is user and system dependent - if you can, it's always good to buy smartly and try several options until you find what works best for you. You shouldn't lose much if any on the resale, and it's part of the fun.
Interesting. The McCormack 0.5, & the Conrad Johnson MF-2250 were the 2 amps I was going to suggest. I'd also say--I've had a "non-A" MF-2250 for years, & I think it sounds beautiful. And I had a stock, (no-"revs") DNA 0.5 in the same system for a few days; it sounded very, very nice.

If you could pick up a stock DNA 0.5 for $500-ish, I'd grab it.