I recently bought a Magellan Roadmate 9055LM. It has a 7 inch screen which is really great. It is the same size screen that came in my wife's Tahoe. Her's spoiled me, so I had to have the 7 inch screen.
You can also hook a backup camera to it. We used it to drive from Virginia to New Orleans and back and it worked great. I bought it on Black Friday weekend from Crutchfield on a great sale for $199, plus I found a Crutchfield $20 coupon and the final price was $179.00. The best part it comes with FREE Lifetime map updates.
After returning from the trip I installed the backup camera. But I had problems with the camera working, it keep blinking on and off. Crutchfield replaced the camera first and after still having problems they replaced the GPS too. Works fine now.
http://www.crutchfield.com/p_360R9055LM/Magellan-RoadMate-9055-LM.html?search=roadmate_9055&skipvs=T
Here are a couple of pics of it installed in my 04 Mach 1. It has a nice long mounting bracket arm this is adjustable in lenth: