It depends what you want, but without doubt, the best area has to be south of Obidos Lagoon. By 2012 there will be 4 five star golf courses within 5 min drive of each other. Furthermore, planning constraints are strict as it is a protected natural area. Once the golf courses are complete and there's no more building - prices will only go one way.
Alot of the resorts are getting expensive now with Royal Obidos charging euros 395,000 for a 2 bed apartment!
For fantastic value -look at Lagoon Village within the Perola da Lagoa resort. Prices are very reasonable at are approx half the price of Royal Obidos (price per sq metre).
For further details - please see Specialists in the sale of discounted off-plan worldwide properties for investment purposes » IQ Property Investments Limited » Welcome
I can also be contacted direct at jeffm@iqpropertyinvest.co.uk