OK. I am sure I will only confuse the issue here; but here goes:
Between PK and Athens? I don't know. I will argue with everybody here about the p|#$ poor visibility at PK. PK just sucks - in my opinion. After listening to everyone in Texas about the great vis at PK and then going to dive it, I was extremely disappointed. . . . . Then to come back to civilization and question people about it, I got two very distinct answers from a multitude of divers. (1) I got "Gee, <<scratching head>> I guess it was 20 years ago when I was there last. I wonder what changed????? Or (2), I get - "Well, I never saw it the visibility that bad. You must have gone on a bad weekend. I don't believe the visibility is that bad."
I call bull%Sit. PK sucks. And now, by the year 2010, there is no good public access to PK. The land around the lake has been purchased by private "home community" developers. All of the access land is privately owned save one or two boat ramps. I am sure I will get an argument out of someone about this.
About Athens: Athens is a nice scuba park. However, it is only 20 ft deep. Take what you will.
Clear Springs Scuba Park (CSSP) is a nice park. It has a max depth of about 55 ft. It is fun. Take what you will.
Other options: I am a big fan of: (1) Lake Murray (oklahoma), Marietta Landing. Murray is just a lot of fun. It is interesting. It is deep. And it is just a neat dive.
(2) Broken Bow Lake (oklahoma) -- Broken Bow is just an awesome lake! Period. Go dive Broken Bow! It is really cool! So is Murray! But; hey Broken Bow is nice!
For most all options around here, you had better carry your own air tanks to support all operations.