I spend a lot of time looking around for new board games and reading about ones I already have. There is one site and one site alone I go to for any of my board game needs: BoardGameGeek.com. It has (I'm sure) a page for every board game ever produced. As well as a marketplace for each game, different versions, user images and videos, forums, similar games, uploaded files, popularity stats, web links, and more. And each game has each of these exclusively for itself.
You can sort games by the BBG ranking, by user ranking, by genre or even by keywords. It's a great way to discover new games. On top of that, a lot of the more popular games have web versions you can play for free in the web links section of the game page.
There's a pretty large community here too. People are always willing to discuss rule clarifications or point you in the right direction for any help you might need. The marketplace is mostly player run and a lot of times, people are even willing to trade games, rather than sell them.
All in all, Board Game Geek is pretty great. Anytime I'm considering getting a game I see in a store, I always check BBG first. It's steered me away from some what would have been bad purchases. So, if you have any major interest in board games, I recommend you check it out. It's pretty awesome.
Also, as a side note, tic-tac-toe is the lowest rated board game. I always thought that was pretty funny.
