I am extremely excited to share that my wife has given me permission (yes, while permission isn't necessarily needed, it's always nice to have that nod of acceptance) to spend significant funds on an airbrush.
After some careful consideration, I've decided on the Iwata 4298 Kustom CS Airbrush. It has all the features people recommend, including dual action, gravity feed, and internal mixing of the paint and air.
In addition to this, I will be getting a compressor with auto-stop (which apparently reduces overheating), a tank to keep consistent air pressure, and a gauge that indicates how much pressure is in the air tank.
Needless to say, I am quite excited to be making the next big leap in my hobby progress. A part of me is a little nervous about the learning curve associated with dual action air brushes, but I'm sure after a while (and a ton of paint!) I will be able to get the hang of it.