I want a facelift
Do you want the site to just look different because you think it's getting old?
The competition has a prettier site?
It's possible to change the color scheme and background imagery like giving a house a different paint job.
Just be careful that it's not too shocking to your current customers who might get confused.
If you're looking to actually increase customer conversion (getting more calls, sales, contacts) you may also want to consider restructuring your site.
Remember, just because the competition has a pretty site doesn't mean it's working for them. Craigslist.org (the number one classified website in the U.S.) hasn't changed it's look in a long time. Many newspapers have prettier classifieds. Craigslist still eats their lunch.
