kegs come in ball lock (pepsi), and pin lock (coke).
ball lock are more common, and the parts are usually easier to find and slightly cheaper. Either will work, but I went with ball lock for the reasons I mentioned. However if I had stumbled upon a great score on pin lock, I would have considered them as well.
Most places will swap out the disconnects for which ever type of setup you need. Some places may not offer it on their site that way, and you may have to call them.
I went with
this system and love it. It has treated me quite well, and I was hard pressed to find a better deal at the time. It is also the same price I paid a little over a year ago. I upgraded the system via seperate orders to 4 perlick faucets, and highly recommend perlicks over standard faucets.