I can highly recommend the Alpine IVA-D300, although the 300 is the old model, and the 310 is the newer one. I don't like the 310 as much as the 300, the additional LCD screen is good if you use the unit with the screen closed a lot, the additional options and interface is nice, but the buttons on top of the screen really just turn me off a lot. That was really dumb of Alpine if you ask me.
This unit isn't very expensive anymore, can get it for around $1000 or cheaper these days, but it's pretty nice. Big 7" PulseTouch screen, XM/Sirius compatable, iPod capable, MP3 capable, DVD, CDR/W, just about anything you can put on a disc, this will read. Lots of tweaking you can do to the sound, great "wow" factor, etc, etc. The only downside is that several functions are protected by the parking brake interface wire (which you need two switches to bypass), so something as simple as setting the clock has to be done in "safe mode". Kinda annoying.