Typically, most tornadoes that hit the immediate Atlanta area are either F0 or F1 jobs that "bounce" a lot and don't stay on the ground a long time. An exception of course being the F2 that plowed through downtown last year and did a ton of $$ worth of damage, though.
In the burbs, generally you don't see a lot of strong ones, but once you start heading West toward Alabama, they seem to get stronger for some reason. Long ago they once said it had something to do with weird jet streams and how they weaken them at some points, but near the Western State line those streams are weaker, so the stronger tornadoes that Alabama typically gets more often "leak over" across the State line more often. So the Western Counties do sometimes see more F2 or F3 tornadoes than the City-proper does. A very rare F4 has hit (maybe 2-3 in many years) and F5 is extremely rare. Again, we typically don't get the "monster" wide tornadoes that stay on the ground for miles and miles like they get out West.
You can buy weather warning radios at Radio Shack and also Kroger stores, that allow you to program specific counties in them. That way you don't have to listen to tons of false alerts for places far from you and you can program only the counties close to you in them.
We seem to get bad Spring tornado seasons about once every 5 or so years here. Last year was a pretty bad one in March, but it quickly dropped off not long after that. Five years before last year, we also had a Spring and early Summer where it just seemed like every freakin' day there were tornado warnings. The last before that one was about 6 years earlier - so, there's sorta-kinda a trend.
Here's a map that shows how many tornadoes hit each County up through 2007 (that were seen and reported):
http://www.srh.noaa.gov/ffc/images/tornado.gif