Sanius, BIOS updates are usually "uneventful." However, when the are "eventful" you usually end up w/ a non-functioning computer. The general rule for updating a BIOS is this, does the update fix or add something that's necessary for you to continue using your computer?
For example, I just updated both the embedded controller and BIOS on my daughter's IBM ThinkPad laptop, in anticipation of upgrading to XP SP2. IBM's website suggested the updates prior to doing the SP2 upgrade. Conversely, I haven't updated the BIOS on my main system (EPoX EP-4PDA2+ i865PE) as there's nothing in the update that will affect how my machine performs.
Bottom line - if you need to do it, do it. If you simply want to putz w/ your machine, think twice. If you do an update, save your original BIOS first. Also, prepare an emergency recovery BIOS floppy. Any number of BIOS sites will provide instructions on how to do this, by adding the BIOS flasher utility nomenclature to the autoexec.bat file on the floppy.