If you are going to do off roading and hit curbs hard, you probably don't want the classic road bike. Hybrid or cyclocross will accept wider tires and will be more what you are looking for. Do you know if you want a flat bar bike or drop bars? CX bikes have drop bars; they also have higher cost. You might be able to find a decent CX bike used.

I think the major brand names are made in Taiwan and the cheap frames are made in China. The components (SRAM or Shimano) are probably no longer made in Japan. Unless you want to drop serious coin or purchase older used bike, it will not be made in USA. Mondo's summary is spot on. One thing to empasize, though, is that you should avoid purchasing a bike from an Xmart. They are crap and most likely assembled by someone who can barely use an adjustable wrench.

I also don't recommend buying a bike online. While you can save some money, you don't get to test ride it and if the sizing is wrong, there will be additional shipping charges and $$ spent at the LBS.

I'm like you and like to understand what I am buying. To that, I say spend more time reading the forums and you'll learn.