The '06 Cobalt was the first car I'd bought. It has been extremely disappointing all the way around. Within the first month of owning it, I had to take it in twice: once because the wiring on the safety harness had been chewed by rodents at either the dealership or a GM facility and had remained undetected until my check engine light went on a couple weeks after I brought it home and next because my ignition stuck and it had to be towed to replace the gear shift in the floor. Since then, I've had to replace the fuel sensor and the fuel pump. Other repairs are pending even now. The car has less than 8000 miles on it. My advice to all thinking about buying one is to research carefully!
Unbeatable gas mileage.
Manufacturing quality is abysmal. I don't even know where to begin to suggest improvement. GM tops the list in terms of sheer numbers for recalls/warnings. Their priority needs to be reinvested in the quality of their craftmanship.