I'll be staying with relatives near Dusseldorf for 5 days and would like recommendations for a single day trip by train. I've been to Koln, Koblenz, Trier, Luxembourg, Brussels, Amsterdam and would like to try some place different. Prefer smaller town rather than major city and 2 hours or less by train (doesn't have to be within Germany though). I'll be there the first week of December.

Also any tips on what not to miss and suggested museums around the Dusseldorf area would be appreciated. It's been 8 years since I was last there. Thanks!

The town of Aachen may be of interest to you. It's about 90 minutes from Düsseldorf by train. It has a Christmas market (starts on 11/24), a historic cathedral, where the German Emperors were crowned and museums. Don't forget to try the delicious gingerbread cookies. Also, take a look at www.aachen.de for more info.
The Kunstmuseum (Fine Arts) in Düsseldorf is probably one of the best in the area.

Aachen is nice, but its Christmas market is nothing special. Muenster, northeast of Dusseldorf, is a much prettier, more charming city and is easily reached by train--its Christmas market has more authentic German crafts and the whole atmosphere is much more pleasant (and you're more likely to have snow--Aachen tends to be greyer and rainier, i.e., Brussels weather). But Dusseldorf's Christmas market is surprisingly good--the city has a noted arts school and many grads have stands at the Christmas market.
While in Dusseldorf, be sure to treat yourself to a dinner at the Schlosser brewery in the old town.
For small towns, one town you should try and visit is Hattingen. It has a delightful old town (if you are interested, I can get you the exact transit details--you take the S-bahn from Dusseldorf, but I can't remember if you have to switch to a bus or if it goes directly).
We spent five months (November 2002-end of March 2003) in the Dusseldorf/Essen area (living in a small suburb) and found it surprisingly enjoyable with lots to see and do.
BTilke (Brussels)

Thanks for the replies and suggestions, I will check out all of the towns mentioned. We are actually staying in Mettmann so I will check on connections from there.

We will be visiting several Christmas markets the week before so may have had our fill of markets by then, but if Muenster has more authentic crafts it may be well worth visiting. I've heard many of the markets are quite commercial now and have little in the way of local crafts.

Does anyone know the name of a semi-outdoor art museum located near Düsseldorf (I think it may have been in one of the surrounding towns) that has a series of small buildings located in a large naturally landscaped open area. You walked along outdoor paths to go from building to building, each one had a small gallery inside. One building housed a small restaurant (I'm not even sure restaurant is the appropriate word, it was a very, very informal setting). I was there over 10 years ago so my memory is a little vague. In any case, I was only able to go thru a few galleries as we had a flight to catch that day and always thought it might be interesting to re-visit. The person that took me there can't remember ever going to such a place even after I showed him the pictures!

I finally figured out how to type the umlaut, yeah!

A few years back I went to Duesseldorf for a week long birthday party. While we were there we visited a place called Xanthen (I may be spelling it wrong) it was a reconstructed Roman village and had an AWESOME spa in it. We also went to the TV tower (great view of the city) and to the old Krups factory (this may be closed now, and we had a guided tour courtesy of our hosts, they were the friends of the owners, so perhaps this isn't the norm?). Those were the highlights of the trip there. We took a cruise down the river....