Weird here's my response to my question (My god, I'm talking to myself 0.o)
PREPARE FOR MASSIVE TL;DR
Twilight: World of Warcraft, Diablo, Skyrim, pretty much anything that is a complete time-hole.
For her patience, smarts and overall ability to cause the nerd-alarms to explode into high-pitched warnings, I see Twi as a huge RPG adventure gamer. Its not that hard for me to imagine her wearing a T-shirt that says "LEEROY JENKINS" at 2 AM, on a personally built computer with a 1920×1080 screen, back arched forward, sipping coffee, keyboard and mouse in hoof, giant surround sound headset perched atop her head, tapping the keys like a psychopath, trying to hold off the mistress of sleep long enough to squeeze out just one more quest to level up her lvl.23 Dark Elf Witch Doctor.
Rainbow: Call of Duty, Halo, the next giant generic shooter the internet hates, and the mainstream loves
Highly competitive, highly puerile, and the tomboyest tomboy you've ever met, Rainbow I imagine as a massive AAA shooter fan. With her ego the size of Molestia's butt, I see her doin' 360 cross-the-map no-scopes, getting collateral-wallbangs and teabagging the SHIT out of the poor twelve-year olds that bumble into her path of domination and humiliation.
Fuck story, deep plot (lol plot), and actually making sense. She's Rainbow Dash and she will kill you and your entire team on Xbox Live and get a nuke in TEN SECONDS FLAT.
Applejack: Angry Birds, Wii Sports, Farmville.
AJ, while she is competitive, I think she would place work and family above pwning n00bs.
She's just too practical a lady and too much of a workaholic to spend hours jumping platforms. Given she has a little sister that bubbling with energy, I expect her to have a small family iPad stacked with her family's high scores on Plants vs Zombies and a little ol' Wii logged with hours of Wii Sports that her friends accumulated.
Rarity: Minecraft, Team Hat-Collecting 2, Dance Central
Maybe its cause its her job to make fabulous things, spend hours accumulating outfits, and just be plain stunning but even after a hard day of being the greatest thing given to stalliondom, Rarity has to unwind.
Maybe completely tear the pentuple decker villa she made out of diamond just to replace it with a mansion that has three pools and a room made completely out of gold, sweet talk her way to getting those oh-so rare limited supply hats on a trading server or just dance like a maniac to "Maniac," Rarity just games to have fun and look damn good doing it.
That and she loves showing off the laptop she personally bedazzled with over 900 pinhead-sized diamonds and purple amethysts in magnificent heart design.
Fluttershy: Pokemon, Nintendogs
Given her shyness and loving nature, I don't see Fluttershy being the in-your-face try-hard that populates the RPG and FPS worlds. But with her seclusiveness, I can't fathom her being a casual gamer.
Maybe behind all the random food bags, lettuce containers and alfalfa pellets; Fluttershy secretly keeps a pink-and-yellow DS that only has two games.
One full of healthy, vibrant rattatas that everypony else would have just mindlessly rendered unconscious; a full flotilla of magikarp that would have been otherwise tossed back out to sea like garbage and not a single gym badge to her name (walking into a building where everyone just wants to beat your pokemon senseless is just too frightening for our butterscotch matriarch).
The other, bustling with the happy yelps and whines of fuzzy-wuzzy Labrador puppies just waiting for their mistress to throw their favorite frisbee, rub their cuddly bellies and show them all the love and affection her gooey caramel heart can usher forth.
Pinkie: I have no f*cking idea.
Maybe she would go toe-to-toe with giant orcs along Twi. Maybe she would run around like a maniac with only a flamethrower, ruining all of Rarity's carefully laid plans to get a Strange Revolver from a 14-year old colt that just hit puberty. Perhaps she would pwn tha shit out of some zombie ass with her army of vegetations. I don't know.
She's effing Pinkie Pie. All I know is she likes the happy, likes being with other ponies, and she makes logic, reason and the laws of existence her bitch.
If she ever gets tired of a game, she'll just somehow put herself in the game. How? F*cking Pinkie Pie science.