The global video games industry houses more than its fair share of creative genius, with digitally-minded auteurs regularly masterminding titles that improve all of our existences on a daily basis.
But which incredible video games mean the most to individuals who make... incredible video games? Which three titles literally changed their life?
That's the question we're trying to get to the bottom of with Game Changers, a new weekly feature taking a look at the favourite titles of the global games industry's leading figures.
And where better to start than with Gabe Newell? As founder of both Valve and Steam, he is a man who has perhaps done more to change the face of gaming than any other individual in the last decade.
Newell's vision has led to a much-loved and community-driven digital download network that is the envy of the entire entertainment industry, and a company which attracts more customer loyalty than any other publisher out there.
And then, of course, there are the games. Half-Life, Team Fortress, Portal; lauded by the critics as modern classics, and cited by envious peers as moments of real inspiration.
But which three video games mean most to Gabe himself... and what are the reasons behind his affection for them?
1) [Star] Trek on a Burroughs mainframe when I was in High School
This was the first video game I ever played, although it's hard to call it a video game when I was playing it on punch cards. My brother and I would type out a move on a punch card machine, grab our deck, put it into the punch card reader, and then wait for our line printer output. Each move took about ten minutes. I was hooked.
2) Doom (1993)
Doom was the game that made me rethink everything I thought about games - control systems, design, rendering. It convinced me that games were the future of entertainment.
3) Mario 64 (1996)
Still my favourite game of all time. I still have vivid memories of all the different levels. The control is still pretty much unrivalled. It convinced me that games were art.
Gabe and Valve's newest baby, Portal 2, will be hitting PS3, 360 and PC on April 19 in the US and three days later in Europe - and it's looking a touch special. Check out our latest impressions through here.
Look out for next week's Game Changers with Media Molecule's Mark Healey...