Just went in May…the 101st Museum in Bastogne is worth a stop. Also there is a museum right at the sight of the Malmedy massacre, Baugnez 44, that was pretty darn good. We found it by accident when we went to visit the Malmedy massacre site. (I didn't realize until then that the massacre was not at Malmady, but to the south at Baugnez.
It's also good going to the Malmedy area from Bastogne because you see the terrain the Germans had to fight through on their northern flank…really makes you understand how tough the Germans had it up there. The terrain is a bitch, especially if you figure the roads (tracks) were even worse back then.
The Bastogne War Museum just outside Bastogne gets press, but we weren't that impressed. It's professional and has some interesting exhibit, but it's more interested in telling a fiction story about Belgium civilians, and American soldier, and a German soldier (POW) stuck in a basement during bombing runs and how they all suffered together and, in the end, they were all the same. Meh.
If you can only hit one museum in Bastogne, I'd recommend the 101st Airborne Museum.