OP, I hope you don't mind me hijacking this thread, but it seems similar to the information I am looking for.

I have around a week in Portugal close to Christmas time. So far I plan to spend a few days in Lisbon, but wasn't sure where else was worth visiting this time of year. From the information in this thread, it sounds like Porto isn't worth it. Should I consider heading down the coast to Algarve area? I'm interested in seeing some castles, and possibly some hiking if good parks exist.

I will probably head to Morocco either at the end of the trip, or a for a few days in the middle, if that impacts what you recommend. I will still have a total of 6-7 days in Portugal though, as the full trip will be 2 weeks.