The only question about this you have to answer is how often do you open applications that use lots of memory at the same time. If you are not doing video editing and photoshop and other similar things at the same time then you do not need the extra memory.
Unlike PC which every time M$ comes out with an new OS it requires more memory, apple is trending on trying to reduce memory requirement for the OS. I have an older Mac with 2GB and it been fine for 6yrs and I have 4 of 5 applications open at all time and have my compute on all the time. The only thing I notice it does get slow switching between applications since if you do not have enough physical memory it uses virtual memory and it take time to swap virtual in to physical.
So if are planning to use lots of memory intensive applications then get the extra because the system will slow over time because of the HDD virtual memory getting all fragmented.
Last edited by Maestro; 11-12-2012 at 05:28 PM.