Well....
Since I am from Germany I have to say (sorry to the US beers) I didn't like any american beer I tried.
My favorites
- Budvar (Which is NOT the same as Budweiser, thats a complex story)
- Pilsner Urquell (despite the german sounding name this is from the Czech Republic, too)
- Rothaus Tannenzäpfle (German beer, rather famous and from the area I live in
http://en.wikipedia.org/wiki/Rothaus)
- Kilkenny (a bit better than Guiness, I think)
- Guinness (the original Irish one, of course)
All of those (except the last two) are Pilsner-beers, so they have a rather bitter taste which most americans I know don't like at all. Also some of our beers here are quite strong (5.5% alcohol or more are not that uncommon, in fact it is hard to find a beer that has less than 5%). That often creates the impression that american beers are kind of "thin" and most germans don't like them because they aren't used to that. So don't be upset when you hear "There is no (real) beer in the US" from a german. They don't want to insult you, they are just used to another kind of taste.
And as you may know: German beer is chemical free (There actually was a law for that from the year 1516 on until some years ago
http://en.wikipedia.org/wiki/Reinheitsgebot)
And a lot of germans still don't want to drink any beer that has more than those old ingredients (like, for example, most US beers), although I admit that they can taste quite good.