Since I'm am a hop junkie it would have to be a good solid IPA or APA [and where exactly is the black and white dividing line between the two?]. If I didn't have anything that needed to be done, or need to drive afterward I might have a DIPA and the spend the next couple hours inspecting the inside of my eyelids.
In defense of the majors [don't kill me please] it might be noted that Coors Banquet won gold at last year's GABF for American Light Lagers. Whilst most of us fans of "real" beer may look down our noses at what my ever so subtle Brother calls "bladder wash", the beers we grew up with in our teens [or college] were excellent examples of the ubiquitous American style. One could argue that they are the ultimate session beer [I won't though].
A couple of FWIWs, although I grew up drinking Coors, the first beer I ever had [drinking was absolutely taboo at home] was a Bud that had spent the previous several days in a hot car trunk, it was the bestest thing I had ever tasted! If warm Bud tasted that good, I knew I was doomed to be a beer drinker. The other FWIW, last evening I actually had a Bud Light, it was either that or a Coors light or nothing. Usually I would have opted for nothing, but I just felt like being kinky instead, I guess