I have a lot of miles with AA, UAL, USAir, BA, and some with DAL. I don't anticipate having the need for any additional miles for a trip in the near future. I recently got the 75K MR Gold Amex on the 2/29 offer. I have never really followed the MR bonus offerings. What are generally the best transfer bonus offers? I am pretty much going to be banking whatever miles I transfer in to for future use - not for any particular trip. TIA.