I'm starting a temporary (they tell me 30-60 days) part-time (20-40 hours a week) job on Monday so I'll be commuting from Decatur (east side of town) to the Virginia-Highland area. About 8+ miles.
I commuted to my last job. It was in Norcross (eastern suburbs).
Commuting in Atlanta is not as great as in other cities. Atlantans have a love affair with their cars (translated: SUV). The streets and interstates are very crowded. Lots of accidents and road rage. Gee, I wonder why? Most drive alone, little car-pooling, and the public transportation system (Marta) isn't all that great, but buses have bike racks and bikes are allowed on the trains. Check Marta's website for more details.
Most streets have lots of potholes and you'll find lots of broken glass and trash, so you'll need some good tires.
FYI: I have Continental Grand Prix 3000s and Vittoria Rubino Pros on my bikes. I get a flat every 1000-1500 miles.

Road and traffic conditions vary a little from one part of town to another. Have you decided on what part of town you might be living in? Do you know where your employer is located? Not being nosey, just knowing these tidbits helps with knowing what advice to offer.