GARMIN C330

It's the best for the money. It does have pre-loaded maps. The only difference between the C330 and C340 is about a hundred dollars and text to speech technology. Garmins are ranked highest among gps systems. As for your job, this unit would have all the necessities you need. Also, as for real-time traffic, fcuk that, it doesn't even apply to Atlanta. If you don't get the C330, you'll just be paying more for what I consider useless features such as bluetooth and mp3 player.