Snap 50: You don't have a ton of choices, but here they are...
Craftsman (except the China made elbow and open end ratcheting styles that were just released) -- I have every US made set they sell and have been pretty darn happy with all of them. The flat and reversible ratcheting sets are my favorites. The locking flex models are decent, but the heads are a bit bulkier than other brands. The reversible cross force wrenches are pretty nice too, but don't fit as well as other styles in cramped engine bays.
Armstrong -- All are US made. Very nice wrenches; they make stubby, flat, reversible and double box configurations. Pricier than C-Man, but you may find a deal if you watch e-bay. I love the double box style with one end that is ratcheting to speed off fasteners and the other that is fixed for final tightening/initial loosening.
Matco -- Some of the older styles are US made. They are essentially the same as the Armstrongs but with a Matco stamp. Beware though, many of their newer styles are imported.
SO -- Very nice, but also very expensive, even used on e-bay. Also, they are supposedly made in the USA, but they are not stamped accordingly.
Good luck!