I have the aquariumplants.com carbon doser. It is an electronic regulator, really easy to use, there is a knob you turn to adjust the bubble count. Before I bought it I researched a bit and found that some people love it and some think it is a rip off, but this was my first regulator and I wanted something simple to use. I would recommend it for someone just getting into co2 like me.
5 lb tank bought on amazon.
Diffuser bought on eBay...rhinox 2000. Might go with an inline diffuser later on.
Drop checker bought on eBay.
Whatever reg you buy, make sure you add check valves in the tubing to the tank so the water doesn't back flow and ruin your reg.
I agree the threads that 10g posted are very helpful