Black hills tj, from all that I have read it seems that Milwaukee is a pretty trustworthy brand for the CO2 setup (includes regulator, needle valve, solenoid, and bubble counter in the MA957 set). You can see it here:
http://www.aquariumplants.com/product_p/pr333.htm
Now this is not the cheapest place to buy it probably but this is a reference to it.
The minimum needed for a pressurized system is: a cylinder/tank, regulator, needle valve, check valve, tubing, diffusion method. If you want to control the flow of the CO2 with either a timer or a pH monitor then you also need a solenoid.
I have heard that the Clippard solenoids typically run very hot (someone actually was talking on the forums about this recently) but it is another common brand to go with. If you were to get a setup like the Milwaukee MA957 you would simply need to get a CO2 tank and have it filled. They also sell tanks on that site but it would be best to go to a liquor store in your area or a welding supply shop and get one and have them fill it (liquor store it would be filled and they would give you a new one when the certification runs out in most cases...just requires a deposit). You can simply add a glass diffuser (
http://www.aquariumplants.com/Aqua_Medic_CO2_Reactor_100_p/am73015.htm) and place it under the intake of your filter. Or for better results you can purchase a reactor (
http://www.aquariumplants.com/Aqua_Medic_CO2_Reactor_500_p/am73008.htm) which come in different sizes and options (they also make them inline to run on the output of your canister filter, for example).
Also to be most accurate and to have a complete CO2 system that requires little monitoring you could add a PH/CO2 controller. The Milwaukee SMS122 is one of the best in the bunch from what I have read.
http://www.aquariumplants.com/Automated_pH_Co2_Controller_MILWAUKEE_SMS122_p/pr209.htm
The pH controller would monitor the pH and flip the electric solenoid on and off to provide constant CO2 levels. This way you don't have a drastic drop in your PH causing high stress to your fish.
Again, I am not saying you should necessarily buy from the site I have referenced it was just a simple place to direct you for further explanation.
CO2 overall can be quite expensive but once you get it all in place keeping it maintained is relatively cheap (considering no faulty equipment of course) as you will probably only need to refill your CO2 tank once or twice a year and it typically runs about 11-15 dollars at a welding supply store, etc. for a 5lb tank. Hope I got all that right. If not, I'm sure one of the pros will step in.
EDIT*** Also someone I know got the fully automatic CO2 injection system from the Drs web site and he said it has run perfectly over the last year. I'm not sure on the quality of all the single parts they use however my friend did say that he would prefer the SMS122 controller by Milwaukee. Here's the fully automatic system from the Drs:
http://www.drsfostersmith.com/product/prod_display.cfm?pcatid=4493