I put a $200 Alpine in the '84.
I've always liked Alpine. The unit is relatively "black" (no shiny chrome trim), plays MP3 discs and Alpine uses a relatively inexpensive cable for iPod connection--and I think the interface is pretty good. Even hooked up the power antenna directly to the Alpine, so as an added benefit the antenna stays lowered when listening to a disc or iPod.
Don't know if the unit is still available, but I'm sure you can get something similar in looks/price
