From Portugal I also like Benfica. Good team and tradition.
They used to show European football highlights every week here in NZ a few years ago, always showing the Portuguese, French, Scottish, Dutch leagues amongst others, and that's how I started to slightly follow the league.
When I was back in Bulgaria a few months ago I got back into following it again. There's a lot of quality present.
Porto are a top team and have performed incredibly well domestically and in Europe over the last few seasons so they have canceled out both Lisbon teams from achieving much. But like you said Bridge-Bhoy, Benfica have a very good squad this season with the additions of Saviola and Keirrison; Porto have sold key players like Lisandro, Cissokho and Lucho Gonzalez; Sporting have also invested with players like Caicedo; so it makes for an interesting season. Last season the surprise for me was Leixoes. They had a terrific season (at least the first half).