One of the first things you need to consider is your budget. Depending on what you buy, $100 bucks won't get you too far at one of those stores. I've been into a specialty store once and decided right away to only choose American breweries (not because we are better, but because it made the process simpler). You could choose a style specific route and maybe get 2-3 each of a few styles.
Going to a specialty shop or even sending someone else to pick out beer can be one of life's greatest challenges.