I'm planning a trip to Washington, D.C. next September and it looks like we will be staying at a Marriot property in Alexandria. I'll need two rooms for 5 nights each and, therefore, a fair number of points (I haven't nailed the number down). My options include transferring from AMEX MR, Sapphire UR, AMEX SPG , or Diners Club. I can also consolidate my spending onto any one of those and build up my points. I'm considering closing the Diners account so transferring from there might be a good option but my bottom line is that I want to get the most value out of my points. Any suggestions are appreciated.