GPS, Internet service, Cell plans?

You're going to need a trucker specific GPS.
Garmin, Rand McNally, etc all offer pretty nice units.

 

Get Verizon's air card also it is great. I use it for umm. webcamming with my g/f all the time. GPS well rand mcnally makes our maps but its up to you. here is a link to a good comparison chart of trucker gps.

http://www.dieselboss.com/truck_gps_review_features.htm

 

Phone service: I use T-Mobile and very pleased with it. I held a call all the way through the gorge in NC and never dropped.
GPS: Not sure of your price range but I paid 109 for a Magellean and has a big easy to view screen. Don't need to pay 500 bucks for a Rand McNally GPS if you check your turn list beforehand to make sure it matches your broker directions and your trucker atlas.

 

Phone: Verizon. Much better national coverage than MaBell.
Aircard: Also Verizon. See above.

I have used many GPS units and I prefer a laptop with MicroSoft Streets & Trips (~$60) WITH the TruckstopPlus add-on ($40)--both available on ebay. Better visibility (as large as your laptop's screen), better scales info, better search options for hotels/airports/walmarts/resturants/casinos... and great support forums for everything. My biggest complaint against self-contained GPS units is the touchscreen keyboard, which, in some units, limit the keys available as you type and therefore cannot find many new roads in its' database. You can zoom in an area with MS and look for the closest roads to an un-named or new road a lot easier than with most self-contained GPS units.

The Rand McNally unit does offer great support for logbook tracking and keeps up with state by state miles for IFTA and can be hooked up to a laptop. The downside is it is expensive and does not offer as many search options for local businesses as does the Microsoft software. It is also not as easy to update the software or construction information as the MS software.

Another issue to consider: if the self contained GPS goes down, you are SOL unless you buy another one to use until the broke one is repaired--then you wind up with TWO units. If your laptop craps out, buy another and reload the software and keep going. AND the software is easily upgradeable and open to programmers that have developed add-ons specific to truckers.