Most gamers have them, and no matter how dinky, huge, or overcrowded they may be, they all go AT LEAST once. Why? Because the gaming store is a key element for the gaming community. By carrying certain products over others, sponsoring tournaments or events, and other support, the stores can essentially determine the "gaming agenda" so to speak.
Take Brainstorm Comics located in downtown Frederick, Maryland. They are a store that carries just about every popular nerd game, and some other various unknown board games as well, plus comics as the name indicates. However, for a while, they had a location dedicated purely to Magic: The Gathering. By establishing that location, they basically said, "We support Magic, come play here." Sadly, that part of the store closed, and its just the downtown location.
Even if the store doesn't necessarily fulfill all of your gaming needs, it's still a good idea to at least buy something from there. The more money and profit the store makes, the better the possibilites for the future can be. Suddenly, the store can afford a gaming table, and then two or three. They may sponser events and have awesome new deals. These oppurtunities come from profit overall.
So go out there and support your LGS!