I'm having difficulty wading through the DAC fog, availablity and features. What are some choices for a good DAC for $500 or less.

I wasn't sure where to post this so here goes. I'm interested in the AKG K701 heaphones, and had a few questions. Will a Harman Kardon CDR-26 power them ok? I won't be able to afford a headphone pre-amp for a while. If you were going to spend $400.00 on phones which would you suggest? Would I be better off buying say a pair of Sennheiser - HD580 headphones, and a Antique Sound - HB1 Hybrid Tube Headphone Amp to go with it. I can do either one of those options.

To make a long story short: one month ago I changed my source components (Theta Digital). The new source is a Meridian G91.
Since the G91 has an integrated preamp I decided to trade in my current amplification (aging Classe CP60/CA300) for a power amp.
Now comes the tough part: I have two options - Balanced Audio Technology VK600 SE and Accuphase A-60. I listened to both in the same setup and I preferred the Accuphase but...
...the BAT was cold (only powered for 5 minutes before listening) and I was already somewhat tired.

Well last night might have turned out with a slight disappointment for CASINO ROYALE where it only walked away with one award for best sound. Well that