the pioneer app radios are junk as well. we constantly have to replace them for freezing up and being overall a turd. plus unless you have your iphone then you have a really expensive fm radio.
kenwood hands down has the best av unit with nav. the dnx5190 is gonna be your cheapest kenwood option. its got bluetooth, dvd with a very easy way to bypass it, and garman navigation built-in. we install these alot and is a great unit. price point is around $699
http://www.kenwoodusa.com/Car_Entertainment/Mobile_Video_n_Navigation/Navigation/DNX5190
if you can live without having navigation and can use it off of your phone or with an external unit then the pioneer avh-2400bt is a great option. still does bluetooth, dvd, and ipod controls. price point is around $349
http://www.pioneer.eu/eur/products/25/111/281/AVH-2400BT/page.html
of course like the guys say after you get the unit then youve gotta get the parts to install it. dash kits run $20, antenna adapters run $18, and the interface to keep onstar, bose, door chime, and rap will around $130, the steering wheel interface runs around $79, and then if you have it installed itll run $100+. the steering wheel controls you can always go back and add later if you want to save some cash right now