Here's the one I bought a while back.
DeWalt, bought at Lowes or Home Depot.
http://www.amazon.com/dp/B000HZI6F4/ref=nosim/?tag=yahoo-tools06-20&creative=380333&creativeASIN=B000HZI6F4&linkCode=asn
So far I love it. For a permanent, fixed position unit, I might have wanted a bigger tank delivering more CFM, but I haven't run into the need yet. I needed something that can be portable if really necessary. I've lugged a buddies' bigger unit around, and it was a MUTHA !!
-interesting to hear about the 2 tank method, I was actually wondering about that. Anybody have pictures of their "home made" 2 tank system? Do you put a check valve between the 2 ?