Nandie,
We were just discussing this a few weeks ago. I saw some beautiful ones near the MARTA station in Chamblee.

Look back thru the threads and see the link that GGG shared.

Dora

Here is the link Dora was talking about. There's been a couple of recent threads on Crape Myrtles, so I thought I'd make it easier for you to find.

Here is a link that might be useful: Descriptive List of Some Crape Myrtle Varieties

BTW, there are also other purple (and even deep purple) cultivars that aren't in the list.

If it were me, I'd probably check with my local nurseries first and see what they have available. Crapes will probably be in bloom right, so you can check out the colors for yourself. When you find a cultivar you like the looks of, check to make sure it is mildew resistant. You might also consider whether it is anthracnose resistant. It probably goes without saying, but I'll say it anyway...be sure the expected mature height is satisfactory for your use. Crapes can top out at anywhere from a few inches high (groundcover types) to over 30'.

If the trees you saw in Athens were in the 10-11ft. tall range, they were probably the cultivar. 'Catawba'. A National Arboretum intro. Another release that is very similar, is 'Powhatan'.
Both are Mildew, pest and disease resistant.

As suggested, it is best to purchase plants when in bloom, to insure you are satisfied with the color and that there is no mistaken identity.

Thanks Brandon for finding/posting that link.
I didn't take the time to do that due to some people that are under 5 feet, lol

Dora

Lately I've seen a couple of RED ones - a very deep, blood red. I'm sure some folks are glad to see true red ones cultivated now.