If you look in the store, under every product is a “more info” button where you can look at each supplement’s article, and the following discussion with questions and answers.
These have helped me a lot in learning about which supplement does what.
Also, always remember that supplements are only effective when your diet and training are in order first (I’m not suggesting you didn’t already know that, I’m just saying it before everyone else).
The order of supplements I like are:
Protein powder (if you consider it a supplement)
Those are what I’d take just about year 'round.
Others I’ve tried, liked, and will probably go back to eventually are: