Here’s something that keeps getting more and more valuable as the airlines continue increasing the cost of traveling with bags. British Midland is offering new Diamond Club members 2,000 miles and free Silver status, which gets you Star Alliance Silver status. Star Alliance Silver status gets you two free checked bags when flying on any Star Alliance carrier (including the airlines that charge for checked bags: Continental, United, and US Airways). Plus, this gets you closer to bmi Gold status, which only requires 38,000 miles once Silver.
This offer seems most valuable to those that don’t fly enough to earn elite status on another airline but can save quite a bit of money by not having to pay for checked bags.
(Tip of the hat to Gary)