Lisbon/Lisboa was my "home base" during a three week trip to Portugal in 1989. Far too short of a trip. Ever since I can't really imagine going back to Europe with out making another stop there. Lisboa must have the friendliest people that I've ever run across in a large metropolitan area. The city itself is very compact, easy to move around in and FULL of amazing places to visit. My favorites were the narrow streets of the very old Alfama, and Chiado neighborhoods and the haunting Carmo Convent ruins. While the city can seem to have many, many tourists, if you think outside of the box and stay off the "Pirelli guide" routes, you can easily feel like you've gone a few centuries back in time. Go to Lisbon and dare to get lost - you'll love it.