Actually, the RAM issues brought up are somewhat of a concern...
Actually, as much as we'd like to say "Oh, no, that only happens on a PeeCee", I think that it bears addressing...
... Your Mac, just like PeeCee's have physical RAM, as well as swap files that it uses to offload RAM information to. If you have a limited amount of ram, say, 256mb, OS X will use more swap file space to help manage the ram requirements of the software.
This is a good thing. It means you can run as big an app as you want (or 100 small ones) and the OS will dynamically take care of the swaps.
The very *bad* thing is that your HD is much much slower than RAM, so every time the OS has to acces the swap file as opposed to the physical memory, you're going to see a major performace hit. The only remedy is to reboot. This purges the swap file(s) returning you to just one. You'll notice a major speed increase, guaranteed.
If you have enough ram (say 640+ MB for most office tasks), you should never notice the number of swap files go over 2 (labelled 0 and 1).
If you want to check and see how your swap files are doing (I reboot after 3-4, and one day had as much as 9!), look in /var/vm you'll see them there. I actually keep a folder link on my dock that I check regularly.
So for the record, I reboot every 2-3 days, because my iMac @ home only ahs 256mb.
