Welcome to the club Hammer!
Air pumps are the popular vote for aeration while fountains are certainly nice, but they do not have the reputation for full functionality and efficiency as the air diffuser design.
Matala (sp?) and vertex are some diffuser brands that I see mentioned here quite a bit. Gast, Thompson (sp?), and Hiflow pumps seem to be popular with the DIY'ers. Pond Lyfe complete systems seem to be a good option.
A PB forum member sells systems and components here...
http://www.hoosierpondpros.com/I have had pleasant experiences with Hoosier Pond Pros. Give them a call and they can lead you on a good path.
Grab a sandwich and start reading the forums that revolve around aeration here...
http://forums.pondboss.com/ubbthreads.php?ubb=postlist&Board=11&page=1Are you looking to do it yourself or buy a system? It is my opinion that the complete systems are a better deal especially if you value your time, but the DIY route is a lot of fun if your into that kind of stuff. A do it yourself system can be done on the cheap, but you forfeit all the bells and whistles.