My impression of mainstream was the Bud/Coors/Miller class and lower. So stuff like National Bohemian (Natty Bo), Genesee Light, and Golden Anniversary fits, as well as all the megabrew stuff.
If we're including the nicer stuff like Sam Adams and Heineken, what about their specialty lines? Could something like Sam Adams Millenium or Sierra Nevada Torpedo count, or are we just restricted to their main staple varieties?
This is just me, but here goes:
'Mainstream Beers':
1) Entire Coors/Miller family
-Coors, Miller, Molson, Milwaukee's best
2) Entire Bud family
-Buds, Labatts, Busch, -Pabst
3) Guinness Stout, Smithwicks, Harp, Bass
4) Sierra Nevada Pale Ale
5) Yuengling Amber Ale
6) Sam Adams Boston Lager, Sam Adams Cherry Wheat (literally, this is freakin everywhere)
-I would cut it off after just Boston Lager, or maybe Cherry Wheat too, because being from NY, more than the above isn't at the local gas stations.
7) 'fruity but prevelent beers' (Blue Moon, Shocktop, etc)
8
) Dos Equis, Corona
9) Heineken
I don't know..there are probably lots others.