Let me add the Chateau Lake Louise to the list that Jasper2009 started. If you like hiking, there are some fabulous trails that start right from the front of the hotel. And since it's a rather expensive property, it might be a good candidate for using a free night cert (I combined a free night and a suite upgrade cert there recently). They also happen to have some of the nicest hotel views you will find anywhere! However, there are no towns nearby that you can walk to, but there are a couple of great restaurants in the Lake Louise village (5-10 minutes drive) if you wanted to dine off-site (the restaurant in the old train station is just excellent, expensive, but you won't be disappointed in the food).

You also mentioned you'll be in Europe. I just booked Le Montreux Palace in Switzerland for next year. Seems to offer good value on the suite upgrade certs there, as there's a very large price gap between the basic room price and the lowest available suite. It appears that all of their suites have lake views, so it's a nice upgrade. Another good candiate for a combination of a suite upgrade and a free night cert.