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.
I forgot about Moosehead - it's an excellent beer. I haven't tried Keiths India Pale Ale - it sounds tempting. Is it a local brand?
Guinness is another excellent beer - though I can't drink very many of them.
I've had Sierra Nevada Pale Ale - long ago. I don't really recall my thoughts on it though. I think I must have liked it - otherwise I'd probably remember more about it.
Is that the beer that has all sorts of yeast, etc.. floating on the bottom of the bottle?
I'm assuming that the other beers (mentioned by Ron) are local beers for him. I like the sound of the Moylan's beer.
What is Fat Tire like? Is that a Chicago beer?
Is Olde Style still a big seller in Chicago? I know that it was the number 1 beer (in Chicago) 20+ years ago.
G. Heilman used to brew a beer that was sold in a green bottle. It was a super premium beer (priced with Michelob) - but I don't recall the name. It too was a very good beer.
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)