(Look at the parenteheses...It took me a while to realize that you were asking for recommendations for use with Cool Edit...)
I use
an E-mu 1820, which obviously gives you more than straight ADAT but works fine anyways. If I was looking for a straight ADAT card I'd look at...
http://www.jdsound.com/store/product1.asp?SID=2&Product_ID=449 This is the EWS Terratec 88D. 1 in 1 out of ADAT, plus stereo RCA and MIDI. It used to be 125 bucks from this place but now it's 150, which is still a good price.
Steinberg VSL2020 2 in 2 out. Musicians Friend and Guitar Center sell this thing for 200 bucks. Solid ASIO as you might expect. I'm not sure if it's stackable like the EWS is. (ARGH...NO. If you're using Cool Edit, which is a WDM program, don't get this. The VSL2020 doesn't support WDM...)
The E-mu 1212M. Same price as the Steinberg, but only 1 in 1 out ADAT, but it gives you some balanced analog and fantastic converters. Still a new card with new drivers... (AGAIN...NO. The infant drivers still don't properly support WDM and no one has a clue when they will...)
The RME HDSP 9652. The next step up at around 500 (compared to 200 and under for the others) It has 3 in 3 out of ADAT as well as SPDIF, 2 midi IO, and word clock IO. Dependable RME quality through the hardware and software.
