The San Francisco 49ers dealt their 2nd round pick (43rd overall) and 4th round pick to the Carolina Panthers. In return, the 49ers acquire the Panthers 2010 first round pick. There was some quality talent there in the second round, but if they didn't want a guy like Everette Brown (or anything else there), why bother making the pick?
Now with two #1s in 2010, the 49ers put themselves in the driver's seat to do a whole assortment of things. Maybe they can trade up, maybe they can further load up the team. More importantly, if there's a rookie cap put in place the team could save even more money against the cap. Not the only reason to make the move, but something to definitely keep in mind.
I'd imagine most folks are happy picking up another #1 for next year. A second and a fourth could fill some needs, but sometimes patience is more important.