There is a brand new digital field recorder from Sony, the PCM-D50, that has received very good early reviews. The pre-amps are supposed to be very good, but keep in mind it doesn't supply phantom power, so you will need to use self-powered mics or a Denecke PS-2 power unit.

Sony PCM-D50 - Professional Portable Stereo Digital Audio Recorder ( $500 at B&H )
http://www.bhphotovideo.com/c/produc..._Portable.html

So the update is that I bought a used 660 with pres modified by "Busman," who is apparently a competitor to Oade. He tore out the built-in mics and disabled the line-in to reduce noise, and installed new pres. I'm anxious to give it a try... It was the same price as a new 660, but it comes with 18 months of a 24 month warranty by Busman.

I'm excited -- hopefully this will be a good match as I expand my audio universe...