Hi there!
I'm glad you're enjoying your stay on the capital of this great little country! Lisbon is surely the more international city.
But I'm afraid you'll be missing out on some really beautiful cities up to the North though, like Porto and Vila do Conde.
At the centre, Coimbra and Viseu are also very beautiful. Next time you come, try to take a train to visit these towns.
If you're a beach person, the South of Portugal is superb... you can't go wrong with Sun & Beach.
I save the last for the end. In my opinion, la crème de la crème is a bit far away, you need to take a plane to reach the fabulous Islands of Azores. There are 9 of them... all very beautiful and each island is unique.
Some are more cosmopolitan, others seem to have been stuck in time. But anywhere you go, the people are great and will get you drunk by offering you a great variety of home-made liquors! It's just the way people are: if you go to their place, you can't leave without tasting some liquor. Or else they'll think you're just rude. Don't worry, they usually throw in a banquet with everything from bread to seafood, so you don't get too drunk too fast. :-D
Hugs! :-D
Spent time in the Douro Valley this Summer-- like heaven but with better wine.