I"m here to make your life easier!
I have the ACIII and I love it. You can control everything from your computer (or iPhone) and they are easy to setup.
Others have the reef keeper as they are cheaper, but don't offer the internet control/configuration. Most people I know who have a reefkeeper wish they had an ACIII.
One thing to note, the AC III is no longer made, as there is a new controller in its place called the Apex. The apex is new, still buggy (V 1.0 are usually that way) and IMO not worth the extra cost.
There have been a couple of AC III full setups on reef central the past couple of days so I can keep watching for you if you want. A good ball park is $350-$400 for the AC III unit, DC-8 (power brick controlled by the unit), temp and pH probes.