There is a similar thread in the ARF forum
http://www.rcuniverse.com/forum/fb.asp?m=8622715
Some of the links are actual manufacturers and others are dealers for one or more manufacturers. Some make/sell only ARFs and others have a big selection of products. A lot of them have a mixture of USA and imported items.

Most of the kits I have personally seen were made in USA and all of the ARFs I have personally seen were made in China or Vietnam. I know some kits are made in the UK and I assume there are some made in other places.

I have built the following kits:
> Great Planes PT-60. Easy build, good durable trainer. Flies like just about every other 60 size trainer
> Tower Hobbies Uproar 60. Pretty easy to build. Simple rugged design. I fly this one a lot
> Great Planes Corsair 40. Not a simple build. I had a lot of help from my brother, in fact he built more than half of it. Not a scale model by any stretch and flies like a sport plane with none of the usual bad stall characteristics that are common to WWII models.
> Great Planes Rapture 40. Still building it, seems pretty easy so far

My brother has built:
> House of Balsa PT-19. He had fuel delivery issues withhis and never did get it working correctly. It didn't survive one of the deadsticks
> Great Planes Super Sportster 60. One of his favorite all time planes. He has a 'spare' kit stashed in case this one dies
> Great Planes Slow Poke Sport 40. He said it was a pretty easy build. He never liked the way it flew and eventually gave it away
> SIG Hog Bipe. Lots of parts but not hard to build. His other favorite.
> FunAero SE5. Still under construction