European Bars

While there's more than one good place for a drink in Salzburg, the only one you really need to know about is
http://www.augustinerbier.at/?id=5&L=1
I've seen Rome bars talked about rather extensively and been to many of the good ones. The names that always pop up are Bir and Fud, Ma Che Siete Venuti a Fa, and any other bar on that street has something good to check out.
Brasserie 4.20 is pretty nice, too, though a bit out of the way.
I don't know enough about the other cities to give you any good advice.

 

Couldn't agree with this more. Augustiner is an amazing place and a must stop. When walking up the winding road to Hohensalzburg Fortress, stop in Steigl too. The beer isn't amazing, but the atmosphere can't be beat. Not beer related, but if you have time definitely go to Untersburg. Touristy yes, but the views from up in the mountain are incredible.

For Prague, the options are almost limitless but some of the ones I remember most are Pivovarsky Klub, U Rudolfina, and Strahov Monastic Brewery (cool location up near Petrin Hill). The atmosphere at these places makes them worth visiting alone, and Pivovarsky Klub has some less often seen Czech beers (at least to a tourist). Also, just look up any tankova pub before heading over there and enjoy the ultra-fresh pilsner.

In Berlin checkout Aufsturz, Dicke Wirtin, BrewBaker, Zur Letzten Instanz , and Brauhaus Georgbraeu. Also try Sophie'n eck for food and berliner weisse, though they will look at you strange if you ask for berliner without syrup.

 

Here is a good article from the NY Times that @mmmbirra posted to the Germany Forum a while back. As with everything in Berlin, it's always good advice to double check to make sure these places are still there. It has been a few months, after all!

I always recommend the Weihenstephaner Restaurant in the Hackesher Markt (near Museums Island). It has all of their beers and some pretty good food, and on a nice day it's good to sit outside and people-watch.

And although I've never been, this place has a very interesting selection. I'm hoping to get back to Berlin before to long so I can check some of these places out.

 

In Prague, the placed called golden tiger (in Czech, of course) was a nice spot to Pilsner Urquell your thirst (hey, see what I did there?). Let's just say that I wasn't the only tourist in there, but, a nice mix of old folks and people who, if they weren't local, were at least better than me at blending in. Just sit down and they bring lagers until you tell 'em no. I can't believe I haven't gotten to more interesting beer places in a few visits there.

And that I haven't explored beer in Rome (too many good wine bars suggested by Romans). In Trastevere a couple years ago I did pop my head into Birreria Trilussa and Bir & Fud (which looked better) -- but, guess what, I was on my way to enoteca...