Having hunted around for a while trying to find a good car stereo that had iPod compatibility (on the back not front), IE one that controls the ipod, not just facilitates playback.... I found the CDX-GT45IP from Sony.
I personally think it's great value at£65 (delivered), the next nearest is around £80 (delivered). Combined with the fact that there aren't that many iPod controlling headunits in this price range (unless you look at some of the really cheap brands).
Anyway; Ipod on the back, Aux on the front, reads mp3 off cd's, and with the right lead (from autoleads) will be controlled by your manufacturer steering wheel controls.
Some (good) reviews here;
4 x 52 watts RMS.
Digital FM/AM/LW tuner.
30 station presets.
Repeat, random play, search and skip functions.
Made for iPod, direct connection.
iPod can be controlled from the head unit.
Bass and treble controls.
Balance and fader controls.
1 switchable pre-out.
Detachable fascia and carry case.