Mrtennis thanks for the thread.
If I may I would like to interject some further thoughts. I like many do not live in NYC or near a major metro area that make auditioning products feasible. I too often have to rely on opinions in order to make equipment buying decisions. For the most part this has worked well but I have been burned a time or two and not necessarily by the seller but by my preconceived notions, sometimes gathered in reading reviews. For instance a pair of Martin Logan Sequels that I heard in a listening room some years back and fell in love with (filed under the category of I will own a pair of these one day)did not at all work well for me in my room and with my gear and I took a bath when I sold them. Money gone, lesson learned. So, I would offer the following points that may seem "elementary" as you put it:
Listen to as much as you can and when and where possible listen to equipment in your room through trial periods or borrowed equipment.
Read reviews and comments with a grain of salt. If someone owns a piece of equipment and is currently playing it in his/her rig they want to believe they made the right choice in buying it so they become natural proponents. To me people are more objective who have had a piece in their rig and moved to something else or who are able to make direct comparison between competing products through experience. But you have to be careful there to because no one wants to admit they moved on to something inferior. After you read enough threads the reviewers/commentators begin to become somewhat familiar to you and you can begin to see some patterns to their comments. Some will ultimately think like you or close to you while others will not. This takes some real time to establish these patterns though. Put even less credence in the rags reviews, they are starting points only as far as I am concerned. You never know what their agendas are (can you say advertising dollars?). Another thing that works well for me is to buy nicely kept equipment used, that way I can ususally live with a piece for a while and if I want to try something else I can get my money back or close to. If you are doing this very often I think a subscription to the audio blue book is a must to have a good idea what things are worth. I try to buy only from people with established feedback here or on Ebay and usually stay away from a "good deal" if there is little feedback to go on as a seller. So, I pay to audition equipment but the cost is low, with the exception of the aformentioned Sequels!