My girlfriend and I were lucky enough to travel through most of continental western Europe last July. I should be able to offer a couple of suggestions, though I have found that my memory is fading fast.

Belgium
we had the most fun here, mostly because we were staying with family and not pushing ourselves too much to see everything while we were there. We did find the people to be the friendliest and most polite of any country we visited. We toured Brussel, in which most of the main city sites are within short walking distance. There are no particularily well known sites, well except for the peeing boy - Manikapis (sp?). You might also enjoy visiting the bar Delirium with the pink elephants. They own(ed) the Guiness Record for the most types of beer in one bar - 2004 (not uncoincidently in the year 2004). You have to make sure to visit a few "friturs" when you are there. The Belgians invented "frites" or what we know as French (or Freedom depending on your politics) Fries. If you happen to be a big WWI or WWII history buff there are plenty of battle sites, monuments and cemetaries scattered all over this tiny country and within short distance in neighbouring France (Ypres, Vimy, the Ardenes, Dieppe, Normandy, etc). We also enjoyed our stay at a small inn near the Abbaye de Notre Dame de Scourmont where Chimay beer is brewed.

Germany
we didn't see too much of Germany, just Berlin. There is a lot to see here and the city is well spread out. The good thing is that the transit system is very easy to use and quick too. We visited KZ Sachenhausen, which was according to stats the worst concentration camp within German borders. Sobering to say the least, but I think important for everyone to see. Sounds like you are on the right track with the beer gardens, that'll be plenty of fun.

Switzerland
also didn't see too much of this country, but did have the opportunity to visit Zermatt which was the only area of the Alps in Switzerland that was open to summer skiing (at least that I could find). We really enjoyed the town of Zermatt, even if it was a bustling little resort town, it was very relaxed. It was especially enjoyable for us considering we had just come from a week in Italy where the weather was always above 30 Celcius. The nice cool weather in the mountains was a great refresher. We had taken the train to (from Venice) and from (to Zurich) Zermatt and I'd have no problems recommending that method of travel. It's not the quickest, but the scenery is wonderful and it's pretty relaxing.

Italy
this country is hot, dirty and smelled bad. It was overcrowded and a PITA to get around in. After this is said though, i would go back in a second. With all the incredible sites you can't miss it....and that wasn't the best part. THE FOOD is unbelievable. Of course I could live on pizza and pasta. I'm sure you won't but don't miss Rome.

I'm sure both of you will have a blast. Sorry to be so long winded, hopefully some of this will come in handy for you. If either of you had any specific questions, even to the point of what train we caught to get somewhere, i'm sure i could find it in the mass of papers that we collected and brought back.

Make sure to take plenty of pics and share with us when you get back.

"Chickens don't clap."