Next years double mile promo (starting January 1, 2002 through ... whenever it runs until) will include Membership Rewards (unlike the current double miles promo).

For those who take US, DL, or CO miles (or any other MR partner), you'll definitely want to consider taking the miles in Membership Rewards instead (if you have an MR account) for potential bonues and added flexibility since you won't lose out now on double miles! (Both US and DL have run recent bonus promos with MR, which would net you even more miles per stay!)