If you like the AK you can always buy an American made one. The ergonomics on them isn't that great, however. For instance, an AR-15 with telescoping stock allows for the user to make the gun fit them better, however, the aftermarket for the ak-47 allows for one to get stocks very similar to the ar-15 telescoping stock. Honestly, though the "best" gun is one that YOU can comfortably use effectively, whether it is an m1a, ar-15, ak-47, sks, etc.
Also, all 4 of the weapons I mentioned are excellent designs, but the quality can be dramatically different varying by brand, or even just the individual weapon itself. For instance, the wasr ak-47s imported by Century can be complete junk or sometimes built decently enough to get the job done. I won't buy one, however, and would rather spend the money on an Arsenal brand AK if I was to buy one.
As well, with AR-15s there are several "tiers." Stay away from DPMS and go for Armalite, Rock River, or Bushmaster and you should be okay. I have heard of complaints about Bushmaster rifles having issues but also hear they have excellent customer support. Colt is considered the top tier of Ar-15s, but are overpriced in my opinion, you could probably be just as happy with an Armalite, Rocker River, or Bushmaster at a price reduction of around 500 bucks at least.
If you go the m1a (or garand as they are cheaper and use 30-06 caliber I believe) you are going to get an excellent rifle if you go Springfield Armory. Auto Ordinance also makes new m1a's but I cannot tell you of their quality as I have never handled one myself.
Hope that helps!