There is much information on the web about the pro's and con's of remodeling but it becomes a real task in finding out about the details in a particular neck of the woods.
So let's see if I can help a bit, whether you are local or planning on moving here.
As a long time Realtor who has been selling in the area of N. Atlanta for the last 18 years or so, I am frequently contacted by former clients and asked whether I can give some advice on the subject.
To begin with, most homeowners who moved into houses built after about 1998 require only a modest degree of remodeling. These homes usually require a facelift of the kitchen and probably the wood floors or carpeting. In some instances, the homes were purchased with unfinished basements and the clients are looking to turn them into a "man-cave" or additional living space for teenagers, or perhaps an entertainment area with a media room. For you folks from other parts of the country where basements are nasty, dark, smelly, storage spaces, you are in for a huge surprise. Here in GA, in the more modern homes, the basements are high ceilinged, spacious, well ventilated and must have a door to the outside (it's the Code). The "terrace level" (fancy word for basement), is usually finished to the same standard, and sometimes better than the upstairs, and the cost is approximately 1/3 of what it costs upstairs. So a well finished terrace level might boast a pool room, a media room, a bar, a living room with fireplace, an exercise room, an office, a powder room and maybe even a bedroom or two. In some cases, the terrace level is finished for guests or the in-laws with a kitchenette and a master bedroom, bathroom, and closet. Often, the terrace level will open up to a pool area with a fire-pit or a weather proof patio. The options are endless. It depends on how much one wants to spend.
So let's talk about spending.....
In the northern suburbs here, one can purchase a beautiful home from $500k upwards. If it is a resale, the terrace level might already be finished. It is very rare to have a newly constructed home with a finished basement as the builders are reluctant to include the cost of the basement in the price of the house, as it pushes the house out of the comparative market. They don't actually come right out and say that but normally state that they want the buyer to have the option of how the terrace level is to be laid out. And on that score, if you are planning on finishing a basement, I would strongly advise that you get a basement architect to do the plan. I have seen some gorgeous homes which were ruined due to the fact that the owners considered themselves "architects" and the terrace level landed up with too many small, dark, pokey rooms that made just no sense.
So, you say. "Please get on with the cost issue". Well, if you are buying a house from a builder (with my assistance of course), and the home is north of $500k or more, then expect to pay between $40 and $60 per sq. ft. And on that score, construction costs are skyrocketing due to everything being more expensive by the day. In addition, you will need an additional $5k for a half bathroom and about $8k for a full. An extra A/C unit to service that area will probably run about $6k depending on the size of the area to be air-conditioned (typically one does not need the same capacity as upstairs, as temps stay more moderate below grade level). Now it's open season on costs for additions like wet bars, appliances etc and of course the media room. (I have seen where just a media room has cost $200k). But overall, if your taste is not too 5th Avenue, you can finish about 1000 sq.ft. very nicely for around $50k-$75k.
Now there's a lot more to discuss on this topic but it needs to be tailored to your requirements, so give me a call, and I'll be happy to help. As a teaser, I am including a link to a basement company. They have some really nice examples.