There was an interesting thread on the Ubuntu User Listserve when one user printed out his free command which showed that he had 24 GB of swap space on the hard drive. While no one advocates 24 GB of Swap (unless you have 12 GB of physical RAM) based on the what was written in the thread. The conclusion is that you should have double your physical ram. The reason for this is that even though with fast computers, you can still use up your physical ram and use a large amount of swap (equal to your physical ram); the catch is when your computer hiberinates and saves the world, you need more swap space also equal to your physical ram, hence swap space should be double your physical ram. I have not verified this but sound reasonable to me.