Our first trip to Europe with the kids (ages 13, 11 and 8) will be to Paris. I'm thinking about Germany for the next one, but I can't figure out a city or cities in which to stay. The draw of Paris was to be able to rent a 2 bedroom flat and settle in for the week in a city in which there would be plenty to do. Other than apartments, it's quite difficult to find acomodations that will sleep 5 people, so I hate to plan a trip where we will drive around a lot and visit lots of cities. Are there any cities in Germany that you think would be ideal base for a stay of between 4 to 7 days?

Depends on what you want to see in Germany! The Rhein River is central to mid-west and "loaded" with castle adventures, sleepy wine-growing villages, cycling paths, and ship tours. The Black Forest (southwest) is great for hiking and swimming, cuckoo clocks and half-timbered old houses (Freiburg, Staufen, Titisee).
Bavaria (south central) for the delights of Munich, King Ludwig's castles, the Zugspitze mountain, painted houses. North for rugged coastline. Is it your first trip to Germany? Some "must-sees"?
Vacation apartments (Ferienwohnungen) are "THE" way to go, I agree! Its SO nice to have a home to come back to each evening! Most will consider a 4-night minimum...
Have you considered 'training' it in Germany? I have never rented a car, and never regretted it! If you stick to a moderate-sized geographic location, trains relieve so much of the stress of getting about.

rach, I've visited Germany twice-before kids. Each trip was of the "stay no more than 2 nights in any one place" variety. In the first trip I flew into Frankfurt and made my way along the Rhine and Mosel. In the second trip trip we flew into to Frankfurt, and drove to Heidelberg, Koln, Strasbourg Fr., Freiburg, the Black Forest, King Ludwig's castles, Rhotenburg, and Augsburg (forgive my spelling). Both trips were great but I haven't happened upon a place where I said "gee, I could spend a week there...." Maybe Bavaria....

rach...I just remembered a third trip to Germany ... part of an Eastern European trip that included Berlin and Leipzig...Berlin is so different from the rest of the places I've vistied in Germany that I didn't even think of it as the same country (and not some place I'll be taking the kids any time soon.)

missypie - you still haven't given us your interests! You've seen quite a bit of Germany - I take it none of the places you have mentioned are on your list of things to see again? I think Munich might be a good base - easy to spend time in the city and easy to take day trips to many different places. Additionally, the time of year could make a bit of a difference too (depending, of course, on what you wanted to do). How long ago was your trip to Berlin? Although I haven't yet been, I have heard there are many wonderful places for families to visit. Especially with older children.

We did a trip to Germany & Austria in 2001 with 2 kids aged 5 & 6.
I agree with the previous post on going to southern germany, where the castles ect will excite the kids. What we did was we had a base town from which we did day trips. Almost all attractions a re normally within an hour drive. It was easy on the kids and less stress for us since you don't have to pack and unpack all the time.

The details of our "adventure" can be found at www.kvictor.us

We took our boys to Germany for 5 days and then drove to Rome for 7 days two years ago. We based ourselves in Munich for the German portion and had a blast. You can easily do day trips as posted above - we also went to Kehlstein Haus (eagle's nest), Innsbruck, toured the Olympic Park and swam there, english garden, palaces, Dachau (yes, i would recommend it highly), with the autobahn, you have a lot of flexibility. Public transporation is wonderful - easy, cheap and on time!