If you install the 64bit you will not be able to take advantage of the pre-load in your video settings. You will be able to add more ram then with a 32bit, and the 64bit is a little faster of an OS but takes longer to boot. The cost difference is null. Its a matter of choice unless you have a need for large amounts of ram I personally prefer the 32bit. There are very few applications that I use that take advantage of the 64bit.
