A True Gamer is someone who likes to play a lot of video games on PC AND Consoles, especially Action-RPG, FPS, TPS, BTA, Survival Horror... he prefers the hardcore games for the challlenge and the fun, with the controller of his choice, but without motion controller.
On PC, a True Gamer always try to play in the best conditions, 60 images per second, the best image quality with settings between high and ultra in 1080P or more, so for his goals he will buy a new graphic card every time necessary to always be on top.
Also, a True Gamer buys every big consoles, the ones which are made by Sony, Microsoft and Nintendo (but not the Wii), he buys them always in the early years of sales, and to play in priority to exclusives titles.
A True Gamer refuse to play casuals games, refuse to move his body for playing, so he refuse to play with motion controller like Kinect, Wiimote or PSMove because theses are made for casuals gamers to play casuals games like Wii Sports.
Outside some cases, a True Gamer never starts a game of nowadays in normal or easy mode, he always take on minimum hard difficulty, or even survivor if available.
At the same price, a True Gamer always prefers games in box, and prefers games that you can play offline, so he's happy to know he can still play in 20 years.
A True Gamer always want the next generation of consoles to be a lot more powerful, not Underpowered.
A True Gamer prefers mature games and male characters, like Kazuma Kiryu in Yakuza series.
A True Gamer plays games like these (just an example):
Bayonetta, Castlevania : Symphony Of The Night, Condemned : Criminal Origins, Dark Souls : Prepare To Die Edition, Deadly Premonition, Deus Ex, Gears Of War, Halo, Manhunt, Metro 2033, Metal Gear Solid... and a lot more.