Hi, I live in Atlanta and have lived here on and off for the last 12 years. I currently live in West Midtown (near Georgia Tech - highly recommend for Tech students but avoid Home Park) and have lived in Virginia Highlands aka VaHi (very close to Emory and very popular with the recent grad crowds), and Inman Park (also fairly close to Emory). I went to Emory as an undergrad and am mostly familiar with where I've lived and that area.
If you live in Atlanta then you need a car. Yes, you can live really close to your school and get by with shuttles and stuff but it will often be a pain if you do not have one and it will greatly limit your housing choices. Reliable public transportation is not a reality in Atlanta. MARTA trains are reliable but their lines are very limited and there are genuine safety concerns during off peak times. The buses are wholly unreliable. I don't have experience with commuter buses so I can't say anything about those. Nevertheless, I highly recommend against living Outside the Perimeter of I-285 (aka OTP). You DO NOT want to drive in from the suburbs if you value your time or your sanity. Yes, it is cheaper to live out there. No, it is not worth it. Anyone who treks in from Smyrna to downtown Atlanta is a much more patient person than I.
If you are going to Emory, here are some suggested areas with a variety of price points:
area immediately surrounding Emory
North Druid Hills
Downtown Decatur
Candler Park
Inman Park
Little 5 Points
Virginia Highlands
Morningside
A little farther out in various directions, you've got:
Midtown
Kirkwood
Oakhurst
For people going to Georgia Tech, I'd recommend Midtown and West Midtown. Georgia Tech is basically in the middle of the city so just look at it and go outward in a circle. You definitely don't want to go too far out and say, try to live in Downtown Decatur and try to go to Tech. It's not worth the hassle of driving back and forth.
For GSU, you're still really close to Inman Park, Old Fourth Ward, Kirkwood, Grant Park, VaHi, Midtown, etc.
Whoever said that you shouldn't live in or buy in Old Fourth Ward (O4W) is crazy. O4W is right off Inman Park and gentrification, for better or worse, has made it a good area to live in, even if it's a bit riskier (and therefore cheaper) than other areas.
There are other neighborhoods I've left off, which I am sure are great, but just wanted to throw my experiences and perspective in the mix.
I have paid (for all decent places): $850 for a 1BR in VaHi; $1150 for a 1BR in VaHi; $1200 for a 1BR in Inman Park; and currently $1600 for a 2BR TH with a garage in West Midtown (at MWest near Tech and convenient to GSU). At the first place I shared a W/D but otherwise I have had my own.
Also, my favorite neighborhoods for living and walking to stuff are: VaHi; Inman Park, and Midtown. L5P is also great for walking around but I wouldn't want to live there. I think downtown decatur would be awesome for that but I haven't ever lived there.