Well i just put in a Pioneer AVIC-D1 touch screen head unit with sat nav in a dual din configuration. It fills in the whole radio area just perfectly with minimal trimming required. Looks totally factory.
Also installed 4 new Alpine speakers in the doors with the fronts having separate component tweeters in the "A" pillar.
There are 2 Alpine amps installed in the left side compartment behind the rear seat. The one 350W mono amp drives a JL Audio 12" stealthbox sub that fits inside the rear centre console. That really works well but make sure you set the phasing to reverse on the head unit since the sub is a downward facing driver. This makes cleaner sounding bass if you pull the driver instead of pushing it into the floor. Don't really know why it sounds better but it does.
The other Alpine amp is a 4 channel amp the drives the other 4 speakers and is 240W total power. These amps are not exceptionaly powerful but they are definitely clean power. Too late to look up the model #'s but if you need them let me know.
The beauty of this head unit is in the ability to customize your sound controls. Crossover spots and slope curves etc. are availiable for sub, mids, and highs and the built in EQ and loudness compensation seems to work very well with these parameters.
You can have about 10 different inputs into this head unit from XM radio, Sirius radio, TV, Rear facing cameras, Camcorder, Multi CD changers, SDVD players, and 2 aux inputs for whatever else you would like.
I put in the optional XM radio module when the system was put in. It was $169.00 CDN at the time including installation. I think I have about $5000.00 CDN into the whole thing with about $650 going into the Stealthbox alone. The head unit was about $2000 but worth every penny. The satellite navigation system is really useful to find your way back home too! Things are still more expensive here in Canada even though it all comes from overseas.
The guys who installed it did a beautiful job. If you can find a good place that installs tunes I would highly recommend it since I would feel terrible if i hacked up my truck.
Well hopefully this helps with your decision when you get your mind set.