I've had my Cobalt for 3 years.
Bought with 80,000km and now have 155,000km on it.
Aside from oil changes and regular maintenance I haven't had to do a thing to this car.
It's fun, zippy, good on gas, and being fully loaded with leather and heated seats I really can't complain about much.
The only problem is one that many 2005 gm cars had - intermediate steering shaft gets sloppy.
Kind of annoying, but have never felt unsafe... just a 1/4" of play in the steering wheel.
My mechanic said it was safe to drive as is or I could spend a small fortune replacing it, so obviously I went the free route, lol.
Other than that it's been a fantastic car!
Leather, heated seats, power windows, a/c
GM should have provided a mass recall on their intermediate steering shafts and used non-plastic parts to prevent the sloppy steering issue.