I'm guessing these are up there on the list:
(dead link removed)
http://www.frontendaudio.com/Earthworks_1021_ZDT_Zero_Distortion_Single_Channel_p/1718.htm
http://www.sweetwater.com/store/detail/201Grace/

Don't forget [[url=http://[/URL]="http://www.mil-medi…"]Millennia[/]="http://www.mil-medi…"]Millennia[/]

It's already been mentioned...Earthworks

A good microphone transformer! No noise. Free gain from 10 to 15 DB. No current draw. Connect that to a straight wire and I think you have it made?

What is the quickest distance between two paths
a straight wire
Ms. Remy Ann David

i've heard some nice things about the gordon model 5:

http://www.gordonaudio.com/

ok ok,

thanks a lot,

and about tubetech ?

A nice sound for sure. But in terms of total harmonic distortion, signal to noise, and frequency response.....I think Earthworks pretty much kills it. And yeah, Millennia makes some transparent stuff too.