Having a kegerator is not only fun and social, it actually makes good fiscal sense!
Kegerator.com did a nice write up that gives some great and specific metrics on economics of kegerator ownership. While the choices of beer and prices will very quite a bit by user, the point is that you can save money and reduce waste by using a kegerator. The other good point they don't touch on in their article is that kegerators make so much sense for homebrewers, where the savings is not only money but headaches by not having to buy or collect bottles and wash them. Moving your homebrew straight from your secondary fermentation to a Cornelius keg means you have only one vessel to sterilize and you'll also not be waiting for carbonation via priming sugar and bottle priming.
Now go get a kegerator if you don't have one. If you do, pour cold one and gloat about the time and money you're saving! Regardless, make sure everyone knows what's on tap with a Keg Cap Tap handle!