If you play online and use the PS Store, then you may wish to update. If you don't, then I would recommend holding off... unless you can think of another reason to update such as using it for DivX etc. Personally I wouldn't update a $400+ console to run DivX when you can buy a $40 stand-alone to do it or use the PC though.
Most sceners keep their PS3 Firmware as low as possible (1.50 or below), for no reason other than hoping a hole in one of the early versions will become public which will allow them to run PS3 homebrew and backups.
Additionally, most PS3 Devs are keeping their PS3 Firmware below 2.10 as that is the revision where Sony plugged the RSX hole. If you do update and can solder, consider installing an Infectus Mod to backup your PS3's flash first. Hope this helps.