Many wide variety music/DVD players available are from brands like Sony, JVC, Kenwood and Pioneer. These can power four basic car speakers which are compatible enough with CD/DVD, FM, USB connections. The Bluetooth connectivity will be a bonus since you won't need any hands-free set. These head units do have simple dot matrix LCD to display any information, but one can get touchscreens. To improve the sound, one can upgrade factory-fitted head unit, and if your car has steering wheel audio controls, then one adapter can be used to configure them to work with your new system.
Many of the cars come with factory-fitted speakers, but their quality is poor. It is always better to install new speakers that can complement stereo head unit in terms of specifications. One can check the recommended RMS power for the car speakers http://www.mcintoshlabs.com/
The subwoofer and car amplifiers (http://www.mcintoshlabs.com/