Tallinn then.. The old town is absolutely lovely; a Unesco World Heritage Site in fact. You can see it all on foot (and it's also a pedestrian area) and is very well preserved. During December then the City Hall square is all decorated and hosts a cosy Christmas Market. In the various stalls you can find first of all everything that is possible to have hand made and woolen: gloves, scarves, hats, jumpers, sleepers, etc., all mixed with wax candles, souvenirs and of course the essence itself of a Xmas market: mulled wine.
The atmosphere is also created by the fact that almost every shopkeeper and staff in restaurants dress in medieval fashion; not only you have quite a few traditional medieval restaurants and shops, but here and there you can find some medieval cart selling candies, chestnuts or mulled wine.
One of the highlights of the Old Town is also Toompea, the very heart of the medieval center. There you can find amongst other buildings the Danish castle, the beautiful Alexander Nevsky Orthodox Cathedral and the Lutheran Toomkirik Church. But what really makes the uphill walk to Toompea worth is the fantastic view of the city, lovely by day, breathtaking by night.
What I really loved about Tallinn apart from the sights was the fact that everybody was extremely friendly and polite; excellent service anywhere, and on top of that everybody speaks English exceptionally well, which helped a lot as my Estonian is a bit.. well, let's just say rusty.