With all the things you've said matter to you, I'd recommend the Honda Rebel as a good first bike. I'm thinking of getting one myself.
84 MPG
250 CC Engine - small, but efficent and very lightweight.
Soft Tail - better handling at higher speeds and more forgiving on rougher terrain
High riding suspension - Better for inexperienced riders in difficult turns and bad weather.
If you're not looking to take passengers, it's a great bike at a great price. I've seen a couple used 2007 models with about 2,500 Miles go for less than 2K.