Backgrounds are what make Web pages interesting and appealing.
One very important graphics issue to keep in mind is the more graphics you have on a page the longer it will take to load. People with slow or modem connections will either avoid your page or just turn graphic loading off when they get to your page. Also, backgrounds can add a lot of interest to the page. A note of caution, though. You need to remember that if you can't sit and look at your page for five minutes without going blind or getting annoyed, then no one else will be able to.