Yeah, they even make mechless units nowadays (no CD slot, just a USB port and maybe an Aux port). My 02 Mustang was the first car I ever saw that could read MP3 off a disc (factory head unit).
I have been pretty pleased with the Kenwood head units. The performance to price has been a pretty good sweet spot to me. Of course, there are several good brands to choose for the head unit (Pio, Alpine). Yeah, an aftermarket head unit, sub-pre-outs should be a given, and really it is pretty common to have a couple sets of pre-outs (sub and full-range).
In my experience, the main brand I avoid for car audio is Sony!
EDIT: Reading through this thread, we basically have 2 votes for Kenwood, and 2 votes against Sony