Atlanta is a really great city. It has a great combination of a vibrant city intertwined with beautiful forests and nature. I'm not exaggerating when I say that you can literally find anything in this city... especially cars.
First place you can come to see interesting cars is one of Atlanta's wealthiest districts, Buckhead. I can promise you that you won't leave Buckhead without seeing at least 3 exotic cars. I can honestly say that I have never been to Buckhead without seeing at least one Bentley. Both of the malls in Buckhead (Lenox Square and Phipps Plaza) usually boast a high chance of seeing something interesting. On a weekend you are almost guaranteed to see a Huracan or a similar car parked in the VIP valet. Next take a quick trip to Buckhead Atlanta, a high-end retail plaza directly in the heart of Buckhead. On my most recent visit I was happy to see a Ferrari F12, Rolls Royce Wraith Black Badge, and an AMG GTR sitting in the parking lot.
If you want an idea of some of the incredible cars you might see, follow Syed (@Lambodoc) and Atique (@atiquester). Both sport some of the coolest cars you'll ever see on the road and in fact are often spotted (more specifically heard) roaring down the road.
Probably the easiest way to find exotic cars in Sandy Springs is to head directly to Motorcars of Atlanta (was Motorcars of Georgia). One of the premier exotic car dealerships in the nation, Motorcars of Atlanta is home to Lamborghini, McLaren, Rolls Royce, Aston Martin, and Lotus. Not only will you find the newest cars from the manufacturers mentioned above, but you'll also find some extremely unique cars in their pre-owned inventory.
Are exotic cars not your thing? Not to fear, Dunwoody can help with that. If you take an early morning trip to Dunwoody's Perimeter Mall on the first Sunday of every month, you can see the largest monthly car show in the entire nation. Caffeine and Octane has every possible car you could imagine. From slammed Civics to lifted trucks, you'll see it all. Often, you'll even see extremely unique cars such as the Le Mans Ford GT parked in the main lot. You can also talk cars with some interesting people such as Roadkill's Mike Finnegan or Youtube's David Patterson (ThatDudeInBlue).
There are many other cities around Atlanta to spot cars. These are just a few examples you can see on a quick trip to the city.