Live in DC, near DCA (20mins) and I want to know which frequent flyer program to focus on. Newbie, don't travel much yet / year but want to start with help from reward flights. Have family in Ireland, often travel there and the UK for side-trips. Dulles is 40 mins away. I think United, AA, or British Airways would all be a good choice? What do you think would be the airline to focus on?