I'm not sure I could narrow it down to just one beer - since there are many different varieties that I've really enjoyed. Some of the beers are best with a certain type of food and some are simply refreshing and delicious.
Not counting brewpubs, among my favorites are:
1. Erlanger - from Jos Schlitz Co. This beer hasn't been brewed (to my knowledge) since Schlitz was sold to Stroh. It was a fantastic beer though - brewed in accordance to the centuries-old Bavarian law (4 ingredients only).
2. Sam Adams - Boston Beer Co. I love their regular lager. (I actually like all of their products - so far.)
3. Brooklyn Lager. It's somewhat difficult to find, but it's very much like Sam Adams.
4. Killians Red - Coors Brewing Co. I actually liked it better when it was an ale, but the current version is still very good.
5. Lowenbrau - Miller Brewing Co. I used to love this beer - then Miller changed the recipe and I stopped drinking it. Recently I bought Lowenbrau and discovered that the old recipe was back (or this wasn't brewed here in the states) because it was fantastic.
6. Yuengling's Black and Tan - A really good, easy to drink beer.
7. Fosters - Smooth, easy drinking beer.
8. Michelob Honey Lager - I love the taste. Nothing like it on a hot summer's day.
Fat Tire!! wow..wish I could sell that here in N.E.!!!
How bout ROCKIES BREWING CO.s HAZED AND INFUSED ALE? Thats a really good one.
Ever been to Key West...have a SUNSET ALE. Thats a good one as well.
For the folks here in N.E. I like GEARYS (Ale, London Porter, and the Hampshire Special)