I drive an 07' Corolla on my 150 day commute. It gets 30mpg in the Winter and 35mpg in the Summer. (80% highway) I'm 6'4" and 290lbs and I'm very comfortable in it. I just crossed 100,000 miles and have done nothing over normal maintenance plus, I bought it used with under 4000 miles for 12,500 and it still books for near 10,000! (Depreciation is the lowest in it's class.)
I'm biased to the Corolla but the right Cavalier, TDI somethingorother, Focus, Sentra, Mazda 3, Civic, Fit etc... will do here just fine as long as its bought with low enough miles and/or has a good service history.