I think calling this particular preference “Appearance” is somewhat deceiving because you can actually set several things here that will make your every day Mac use conform to your personal likes. For instance, you can do something as simple as change how the arrows work on the scroll bars for your windows to set how many different servers you may have open at once. One of my favorite options is the option to jump to the next page in a document by simply clicking in the scroll bar. All you have to do to set this is click in the appropriate box.
Another one I like is the ability to double click a window tool bar to minimize the window. I know, I know, I can do that with the little yellow button, but I can hit the tool bar faster than I can hit the little (emphasis on little) yellow button.
Take a look at the options for how many recent items you can view. Listing the maximum number (50) Applications can be a quick way to get to your applications and some people prefer using that method. In the old days of OS 9 you always went to the Apple menu to get to your applications and this mimics that.
Last but not least, I recommend that you take a look at the “Turn off text smoothing for font sizes” item and set it at 8. It makes it much easier for you to read what is on your screen. Particularly for those of us whose eyes aren’t as young as they used to be.
Qualifier: I am running OS 10.5.2. If you are not, you might see all of these options in your preferences.