I've made some very unwise car buys in the past, and from them I've learned some valuable lessons. Rather than make a long comment here I'll write some of them up for my own blog. If you like the car then keep it. I highly doubt you'll be able to sell it for anything close to what you owe. I've never been able to sell a car on my own; I just trade them in or drive them until they fall apart and donate them.

I've long since stopped thinking of a car as an asset, depreciating or otherwise. A car is nothing more than an appliance; a $20,000 toaster (actually, the most I have EVER financed a car for was $12,500 for a 1993 Mazda MX3 that I bought in 1995.) All of my cars have been used.

You might be able to save a little bit each month by shopping around for car insurance, which you mentioned was part of your monthly costs. Loyalty gets you nowhere when it comes to car insurance. When I was a "single male under 25", I paid State Farm through the nose for years before I got fed up and switched to Liberty Mutual for half the payment. When I moved to New Jersey, I found Allstate to offer me the best possible rate.