What I'm doing is focusing on the ranking of the school and then also the location. I want to go to a decent school, but the most important thing to me is the location. I want to go to a school somewhere in the South. Are there other things I should be looking at?
That's a start, but there are a lot of other factors that come into play. For example, if you are really interested in environmental law, you might want to add that as something to look at when considering schools because not all schools have a program specifically for that area.
I bet Anne will have a lot more to say on that front when she logs in.
Eliminator, you know me too well.

Steely, where you're at right now is definitely a solid start, but there are many, many more things that you can (and should) consider when selecting law schools. Location and ranking are good initial points, but also consider:
"National" vs. "Regional" reputation: This ties in to what you're already looking at with rankings. Typically, the higher a school is ranked, the more "national" it is considered. The more "national" a school is, the easier time you'll have getting a job outside of your school's region upon graduation. To use an extreme example: A recent graduate of New England Law (a school in Boston) would likely have a much harder time getting a job in California upon graduation than someone who attended Harvard Law. This is due to what essentially boils down to "brand recognition" and reputation. Employers in California are much less likely to have heard of and dealt with students from New England Law, whereas they will have heard of Harvard. However, a graduate of New England Law will probably have no trouble within New England in general, and Massachusetts in particular. In your case, since you already know you want to practice in the South, you can tailor your search to both "national" and "regional" schools within that region (i.e., Emory Law would be an good example of a "national" school, whereas the University of Alabama Law or the University of Georgia Law would be a good "regional" schools).
Accreditation: This should go without saying, but make sure that the schools you select have been accredited by the American Bar Association (ABA). Graduates from unaccredited schools often have a much harder time finding employment, and their degree is not at all portable (meaning, they usually have to stay in the state where they got their law degree if they want to practice law).
Class size and section size: A lot of students don't think about this, and they should. Are you comfortable being a part of a very large incoming class (Harvard, for example, has over 500 incoming students every year)? Or do you want to be a part of a much smaller school (Notre Dame, for example, only has around 180 incoming 1Ls every year)? Although larger schools make every effort to reach out to every student and make sure everyone is taken care of, the fact remains that a larger school will probably be much more impersonal than a smaller school. Is "being more than a number" or a close-knit student body important to you? If that's the case, then you should consider only looking at smaller schools.
Religious affiliation: This doesn't come up often, but it is worth considering if religion is important to you. There are a few schools where religions is very much a part of the school, not only in everyday life, but also in discussions. BYU Law, in Utah, is the primary law schools for those of Mormon faith. Cardozo Law (part of Yeshiva University, in New York City), has a strong Jewish tradition. Notre Dame is imbued with the Catholic faith (and even has a chapel on site within the law school), and Boston College lauds its Jesuit heritage. All of these schools integrate their religious roots into their discussions and curricula; if that's important to you, then perhaps one of these schools is a good fit.
Specialties and programs: Like Eliminator said, if you're strongly considering practicing in a specific area of the law (environmental law, health care law, international law, tax law, etc.) then you should definitely start by looking at the schools with strong programs in the specialty you're interested in. Not every school has an environmental law or health care law program, while others are known nation-wide for their strength in those departments. Start by looking at each school's website and seeing if the specialties are mentioned. Schools are proud of the things they know they're good at, and will have tons of info on them if they have the specialties you're looking for.
Job prospects upon graduation: Particularly in this economy, thinking three years into the future at your job prospects is a smart move. Take a look at a few things: Does the school have a Career Services Office on site? How many counselors do they have working there? Do they host on-campus interview programs? What kind of resources do they have available for students searching for jobs? What is the school's employment-upon-graduation rate? How about employment rates nine months after graduation? Where are their graduates working? All of these things are important not only for you to gauge how successful a school is at producing employable attorneys, but also to get you started in thinking about what you want to do with your law degree.
Cost and scholarship opportunities: Law school is expensive. Have you thought about how you'll pay for it? It easy to just say you'll take out loans, but with tuition for many schools creeping past the $40k mark, that means taking out at least $120k in loans just to pay for tuition (and we haven't even looked at living expenses). That's a LOT of money that you'll have to pay back. You HAVE to consider if that's something you're comfortable with. If it's not, then perhaps you should only look at schools with in a certain cost range, or consider in-state schools for where you're currently living (which are usually much cheaper for residents). Also look at which schools offer scholarships and grants. Some don't, and all they offer in the form of financial aid is loans. If you're not comfortable with taking on just loans and want a school that also gives merit or need-based aid in the form of "free money," then make that part of your consideration.
Academic environment: Some schools are very competitive, others are not. No school will ever advertise this on their site (they'll all say they're "convivial"

), but if you Google the schools you'll get some pretty good student feedback.
Proximity to home: Consider if being close to family is important to you. If it is, that will drastically narrow down the schools you're interested in, simply by sheer location.
Extracurriculars: Smaller schools tend to have fewer student groups and extracurriculars than bigger schools. If a vibrant out-of-class student life is important to you, that may be something to consider.
I could go on

, but those are some of the most important ones that I would consider if I were choosing a school to attend.