I have two Magellans, and they are both miserable excuses for GPS. Their map updates are really bad.
I just got an iPad, and there are many nice GPS apps. Just used a couple on a trip to Wisconsin and back: just about 1000 miles. So much information, and so nice a detailed display!
So I suggest you take the money not spent on a dedicated GPS, and you are well on your way. BTW, you need to get a model that CAN connect to AT&T or Verizon, but you don't have to actually take their service. That's the only way to get a built-in GPS chip.
Google Maps is nice, Apple Maps not bad, CoPilot and MotionX are very nice. All are free.
