Do you design your sites with only one browser in mind?
If you are it is a very big mistake. Why should you shut out a large percent of your visitors just because they are using a different browser than you?
If you don’t believe me look for yourself. Try looking at your hard work with another computer and browser. If you are shocked to see what you see, you are not alone. There are many different compatibility issues with different browsers and with IE7 due out any time now there will be more.