Here is a quick tip that you probably already know about, but I'm an idiot and I just found out about it a week ago. There is a setting in Windows XP called ClearType that makes your fonts render more smoothly. Predictably, this is turned off by default.
I didn't know I needed glasses until I started living 1/3 of my life inside of Excel. It isn't easy on the eyes, so you have to take care of yourself. This setting actually makes a huge difference. It should be on by default in Windows 7, if you have Vista you've already gouged your eyes out so it doesn't matter, so here is how to turn it on in XP:
1. Go to Display in the Control Panel.
2. Select the Appearance tab, then Effects.
3. Check the box for "Use the following method to smooth edges of screen fonts", then select ClearType from the drop down list.
4. Hit okay, apply, etc.
Just remember, it won't make your pie charts look any better.