A combination of Wikipedia/Amazon.
I actually pay attention to reviews. Also, net stuff from forums to amazon, etc....
I would pay attention to reviews, but so many albums are hailed as the best thing since sliced bread that positive reviews have lost all meaning.
I download first. Then buy things I like
Interesting, how do you use Wikipedia (to find new bands I mean)?
If you're looking for rare items, eBay is the way to go. Especially for box sets and demos.