I needed something reliable, got good gas mileage, and could carry a bunch of stuff. My 2008 HHR does all that! I average ~26 to ~27 MPG and have been amazed at all the stuff I can carry in the back with the seats folded down. Extra storage UNDER the floor is nice also when you want to keep handtools hidden. I could use a little more leg room for my left leg when driving though [the wheel well kinda sticks up there] and the center window controls take some getting used to. Heat/A/C work wonderfully and sound system is nice also. Lots of headroom is nice and yeah, that cargo capacity =)
Cargo Capacity & Gas Mileage! You can comfortably fit four... five if you must. XM radio has also become a "necessity" for long trips.
Needs a better center console for cup holders, map storage, etc. Need a better spot to put your left foot while driving. If you have long legs, it can seem a little cramped.