If you're using a computer with an LCD screen (i.e. a laptop computer or a desktop with a flat screen monitor) and it's running Windows XP, check to see if you've got
ClearType turned on. Following
this tip found via
Lifehacker (my favourite site on the interweb right now) I turned on ClearType and increased the screen refresh rate for my computer at work and I am seriously impressed by how much of a difference it's made, and how much easier it is on my eyes.