I have always said there are two kinds of luggage: carry-on and lost. And with airlines now charging as much as $20 to check the first bag, why would I pay the airlines to lose my luggage? They used to do it for free!
I haven't checked luggage on domestic flights in nearly nine years, and that was long before the airlines began nickel-and-diming. My reasoning? It's not about how much the shipping costs, it's how much your time is worth! I save two and a half hours every time I fly because I don't have to wait in line to check my luggage, don't have to stand around the baggage carousel and don't have to schlep my bags to and from the airport.
Instead, use FedEx three-day service, or UPS, or even FedEx ground. It's not that expensive, and you get door-to-door service.
Another tip: If you need help packing all your belongings into one small carry-on, check out the Web site OneBag.com. And remember to look at each airline's rules for carry-on baggage sizes so you don't get stopped at the gate.