Mark
I've played two courses around Lisbon which have been mentioned here. Praia del Rey about 30-45 minutes to the north, it is well worth looking at.As well as Obidos, there is a lovely fishing village nearby called Peniche, full of nice fish resturants, should be no sign of any lager louts.Just outside Lisbon in Cascais is Quinta da Marinha- Oitavos, I really liked this one, also worth looking at.
There's probably more to see and do in Lisbon then the Algarve, as mentioned the drive is not difficult on the motorway and about 3 hours.
Worth looking at in the Algarve are San Lorenzo, Penina, Vila Sol, the Vilamoura courses, Quinta da Ria, Vale do Lobo. To avoid the masses, look for a pousada as Sean suggested and explore from there. There is one in Sao Bras de Alportel, centrally located but away from the resorts.