The most common body shape for north american built guitars is the shape made popular by Martin, & called a "dreadnought". The majority of factory made guitars utilise a tapered dovetail neck to body join which has been cost efficient for assembly lines, but has a long history of structural failure over time. Not that it can't be fitted well, but that it often hasn't been.

I have also built the 'dreadnought' shape but although external appearances are somewhat similar, my construction techniques are quite different. Most notably, I prefer the same "Spanish style" of neck to body join that I use on Classic & Flamenco guitars. I'm also into thin back & sides, very thin finishes, and exotic hardwood bindings (instead of plastic).