Not sure what features you would be looking for in a "modern" radio replacement.
But one thing nobody seems to talk about here is having the existing radio modified by Becker (the original manufacturer), to provide an auxiliary input.
I sent my factory radio to them, and they added an internal Bluetooth interface inside the unit.
So when I enter the car, my phone automatically connects to the radio, and I can stream music from my phone, from my Sirius satellite subscription directly into the radio.
The Bluetooth is only for music, you can't use the phone through the radio for calls, just music.
Cost for this factory modification was $148. including paying their shipping.
www.beckerautosound.com
They will also alternately add an audio input cable with jack that you can mount the jack (like inside the armrest) if you'd rather use a cable.
For a single-DIN radios, I think that does a majority of what you might want.