The lump sums payable will be decreasing from now until 2012 because the interest used to calculate them is blending in corporate bond rates. This maybe the last year a lump sum may make any sense for someone who is in relatively good health.
Also remember the PPA of 06 funding deficits kicks in this yaer. If under 80% funded, the lump sums are limited to 50% OF THE CALCULATED AMOUNT AND THE REMAINDER MUST BE AN ANNUITY. The annuity may be converted to a lump sum later if the plan allows.
Also BEWARE the 50% amount is only good to the limit up to the PBGC 50% guaranteed amount. For example, if your lump pension calculates to $800K at age 55, you might think you could get the $400K and the remainder as an anuity. WRONG! The PBGC limit is $347K for a 55 year old.
Then note if the pension is less than 60% funded, no lump sums can be paid.
FOR YOU, you must find out the status of your plan as these limit go into effect April 1, 2009. You might want to get your lump as of March 1 by going in February.