Hello Centurion.
I use a variety of paints for different purposes. I took a long period of trial and error to find what paints I was most comfortable w/ in which application. My recommendation is that you should do the same, try lots of different paints on lots of different types of projects to establish a "palette" that you are comfortable w/.
For the most part, I use an airbrush whenever I can get away w/ it. Mostly I shoot Testor's Model Master enamels through my airbrush. I find them easy to use, easy to clean up and they give good opaque coverage in very few coats. I may be in the minority though, I think most modelers prefer acrylics when airbrushing.
When forced to paint w/ a brush, I prefer Apple Barrel Craft acrylics, or a similar brand. They are very cheap, have good opacity, you get a lot of paint for your money and they come in a huge selection of colors. They do not have popular military colors though, so you may be forced to look elsewhere for those.
I have heard that Andrea, Citadel and Vallejo make good paints, but I have little or no experience w/ them. There is probably something about them in the Painting and Airbrushing section of these forums.
I have also heard that Tamiya paints aren't so great when applied w/ a brush. My few attempts to use them that way lead me to believe that's true, but I don't have extensive experience w/ them. If they are working for you, that's all that really matters.
For techniques, I'm currently working on a figure painting W.I.P., but I have a lot of projects on my plate and might not get it up for a bit. In the meantime, there are lots of other guys around here that do some excellent work.