I've only kept track since June (when I joined CAG). Since June 13th, I've spent $484.29 cash on video games (including all game-related investments), and gotten $430.60 back from selling (all stuff bought after June 13th).
So in total, I spent a net of $53.69 on video games. I have bought 31 GameCube games, 3 Platinum Wavebirds, a GameCube Gameboy player, a 251 block memory card, a PS2 slim system with controller, 58 PS2 games, 5 PS2 8MB memory cards, 2 Nintendo DS Lite systems, 35 DS games, 58 Gameboy and Gameboy Color games, 2 Playstation games, 2 360 games, an Xbox Live Vision Gold pack (includes 12-mo Live code), and a wireless guitar for the PS3.
Man, I love this site! Flipping FTW!
PS, I spent a lot more cash in the first half of 2008. Probably a few hundred on a couple dozen PS2 games.