Two scenarios - I had a friend who "Er'd" but took the lump sum and rolled it over - turns out based on his projections he would have had the same effective amount whether he rolled it over or stayed the extra 10 years to take the full retirement at 65. Now he's working (why the ER is in quotes above) for one of our vendors and has yet another income stream and opportunity to have another retirement plan. Very good decision on his part (except for the not really ERing) financially.
I checked into the ability to rollover a lump sum of the defined benefit pension plan here and there were some very restrictive rules on it as well as a serious penalty for the ER portion. Make sure you check the fine print - for example, the lump sum option is not available until I am 55 or I have worked there for 15 years. Also, there is a 2% per year reduction in the amount assessed for the pension benefit. Also, the interest rate (for lack of a better term right now) used for determining the value of the lump sum as compared to the monthly payments can make a beig difference in how much you get. I believe the lower the current rate, the bigger the sum you get. In any case, as always check the fine print.
Bridget