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!
b_limo
I'm gonna slightly disagree with Steveaudio here. While the stock DNA 0.5 is undoubtably a good amp, the 0.5 Rev. A is in another league. And if you can get one for an extra 500 bucks or so and still be in your price range--well--how many times can you jump several levels of performance for 500 clams in this hobby? Long story short, buying an already upgraded DNA 0.5 is a huge bargain considering what the upgrades cost and the significant performance advantages they provide. Just my $0.02 if you're considering a DNA 0.5.
Did CJ make an A version of the MF2250? I had a MF-2500-A ,,,never should have sold.Sweet and powerful!
I only have experience with the McCormack DNA-1, but I just jumped to it from an Adcom GFA-545. The difference really is astounding. My 4-ohm Polk LSi9 speakers are completely transformed by its low-impedance capabilities. Got it used for a good bit less than $1K.

It's already in the hands of SMc Audio, for a Silver upgrade. Using the 545 in the interim. I miss the McCormack.