Please tell me all about the great things to do and places to eat in Lisbon

[soupplate]

DH and I have a week in Lisbon in early December. We like to walk, we like history, art, eating, drinking, looking in interesting shops. Do you have any recommendations for the city and surrounds?

The aquarium is good and the cable car is fun, the Belem Tower and the Mosteiro dos Jeronimos are worth a visit. There's a Gulbenkian Museum (although I haven't been to that).

Sintra is a great day trip, lots of historic palaces to wander around.

Cascais and Estoril are also worth a visit, and DH always raves about Guincho Beach - the Fortaleza there has a fancy restaurant which is supposed to be very good.