There have been discussions here about Uggs before and the take-away was that they were terrible for your feet with no support to combat all day walking over cobblestones or anywhere else. Being from Orlando, if you haven't lived or traveled in European cities in the past, you are probably not aware of how "rough" the walking will be compared to home or how much you will be on your feet every day.
I've found that shoes/boots with lots of support and made with breathable but water resistant Gore-Tex or something similar are the best thing for walking in the cold, wet, maybe snowy, slippery and rough conditions you will experience in all the countries you list in December. Good, breathable polypropylene or wool socks will also be much needed and appreciated by your feet.
This is a good website for showing the variety of shoes and boots that are made with Gore-Tex: http://www.gore-tex.com/products/women/footwear/. Yes, most of what you will see there is athletic, but not all. You can find these and other similar shoes and boots online or in stores from the usual suspects: Amazon, Zappos, the Walking Company, Foot Smart, REI, etc.
I have worn somewhat athletic shoes (not sneakers) with ankle support on most of my trips to Europe, including the first one when I was 30. I never regretted having those shoes/boots for walking around and usually switched to something "nicer" in the evenings when going out for dinner. I definitely regretted not having some good walking shoes like those on the one trip I decided to be "fashionable" and didn't take them. Big mistake.
At the moment, my favorite brands for support and comfort are Ahnu (available from lots of sources) and Abeo (only available from the Walking Company). I have both the Ahnu waterproof Sugarpine and the higher-topped water-resistant Montara boot. Both are designed for lots of walking. Both keep my feet warm and dry. With the right socks, my feet are comfortable in them both here in dry, hot AZ and in wet, cool WA.
I also have some Abeos, but they are sandals or flats and are not what you would need for your winter trip. Abeo does have some walking shoes that are enclosed and don't look like typical sneakers. I haven't tried them, so I can't say anything pro or con about them.
I mention these 2 brands because not many people know about them and I've found Eccos, a brand often mentioned and one that I have owned, to not be supportive enough for me.
Enjoy the markets. I lived in Nuremberg through 3 winters and the market was wonderful every year. I still have the red-velvet angel tree-topper I bought there. That's the only one I've been to, but I'm sure they will all be great.