I've heard good things about this GPS receiver:
The BU-353 is widely used for carpc navigation, too. Plenty of threads about it all over then 'net you can read.
On the software side, GMPC (discontinued) is a favorite, along with iGuidance, CoPilot, and a bunch of others.
As far as radio goes, I hate XM with a passion and won't purchase that ever again, so I can't recommend any XM radios. If you want a standard radio that can also pick up HD radio, then I recommend getting a Visteon HD unit. You can find them online for about $25 if you look hard enough. Then you pick up one of Mitch's HDR-USB cables so you can connect the HD unit to your computer, and for under $75 you have a fully functional radio - much better than any of the usb radio kits that you can buy, and quite a bit cheaper, too.
Are you active duty AF? I'm starting terminal leave next month, after 22+ years - 10 of them at Tyndall. Just wondering.