@dtm1997
If real estate is part of your investment portfolio, and you have the means, I highly suggest you invest in an Atlanta intown property NOW if your end goal is to have a place here one day. Rent it out or make it a permanent AirBnB/VRBO place and have a professional management company look after it. Even if you break even the first few years after management fees/HOA dues (if you are getting a condo/townhome), upkeep after tenant leaves/etc, something to keep in mind: Rental rate increase in Atlanta is one of the strongest in the nation, as well as occupancy rates. That is not going to change as the influx of people and jobs to Atlanta is heavy. Builders can not keep up with the demand for housing in Atlanta. Guess what? At some point, you just can't build anymore in Atlanta unless you build up, and the acquisitions and development game in Atlanta is getting prohibitively expensive. Within 5 years, you will be making a profit, and that's not including appreciation over your 20 year time frame.
I am going to echo what
@MWBATL said. Old Fourth Ward, for my money, is probably the best area in Atlanta right now. Prices are still fairly reasonable comparatively speaking versus other well developed and "matured" areas. Where I live, I'm a 2 minute walk through my development and our dog park to the Beltline. Once on the Beltline, I'm a 5 minute walk to all the Inman park restaurants/bars on N Highland Ave, 15 minute walk to both Ponce City and Krog Street (both are direct opposite end on the Beltline from me), and an 18 minute walk to Little 5. It's like I get 4 awesome neighborhoods for the price of one! Oh, and I can Uber to Virginia Highlands within 5 minutes and Downtown Decatur within 18 minutes. If I don't want to deal with the crowds on Gameday, I can take a 20 minute walk to Marta to get to GT campus. The level of walkability is off the charts. You can literally spend months in this area without starting your car up...unless you have pesky friends and family in the burbs unwilling to drive down to see you. F them.
O4W gets my vote here.
Midtown, IMO, is getting too congested and most of the restaurants are chains. Rent is skyrocketing and you don't get much. I lived in Midtown years ago, right on 14 street and maybe a quarter of mile from 75/85. It took me 20-30 minutes to get to the freeway because it was so congested. I shudder to think how long it would take me now.
Buckhead...yuck. Overpriced, and you don't get much...except for the whole "I live in Buckhead" thing, which if that's what you want, more power to you. Shopping is better there, but of course, have fun with traffic and parking during the weekends.
Places like Kirkwood, Grant Park, and Reynoldstown are pretty cool. You just don't get the variety of restaurants and things to do like you do in my area. Walkability isn't as high, though it's not bad.
Keep in mind they are still expanding the Beltline. There are still pockets where you can make a great investment, but those areas are further away from GT campus.
In 20 years, I can foresee Atlanta becoming a housing nightmare much like NY city/San Francisco/Seattle.