@vincentdante
Try Debian. It's a universal operating system that right now supports the Linux kernel officially, experimentally the FreeBSD kernel and in the future most likely the Hurd kernel (maybe it already does, experimentally). An operating system kernel is a core element that acts as a bridge between the hardware and low level OS functions, such as assigning CPU time, memory allocation, input/output, etc. Debian was one of the first Linux based systems and is widely supported. SteamOS is, in fact, based on Debian (Stable).
I'd recommend Debian Testing. The "testing" branch is more stable than many release level distributions (like Ubuntu) and features mostly recent software, but maybe not bleeding edge. Stable is a production/server style distribution where everything but security updates is frozen, virtually eliminating the possibility of breaking the system with untested updates.
As
@Gilrond said, installing Debian now should be easier than ever thanks to the installer supporting UEFI. You can have a dual or multi boot system and try out as many things as you want.
Now the real issue here is
Linux Gaming. Keep in mind binaries or executables are architecture and operating system dependent, meaning a Windows binary will not run in Linux, period. The way we do it is through third party software like, in this case,
Wine, which provides runtime libraries to interpret Windows programs and make it possible for them to run in a Linux system. As you can imagine this may unleash a series of issues and problems, but at least it's possible. Can't say the same about running Linux binaries in Windows
Now, what I root for is
native Linux gaming. That is, games with real Linux executables. There are several examples, mostly from indie developers, such as Trine 1 & 2, Anomaly Warzone Earth, Expeditions: Conquistador, Shadowrun Returns, and hell even Metro Last Light. Valve has, for obvious reasons, put a lot of effort into porting their Source engine, so right now you can play Portal, Left 4 Dead, Team Fortress and Half Life in Linux too. Most of the time running native games in Linux is as easy (or even easier) than doing it in Windows.
So if you decide to try and play games in Linux, I'd recommend playing native versions first. Once you feel comfortable with handling configuration and settings in Linux, go ahead and try Wine gaming.
A cool technical aspect of Linux is that, being open, it is highly customizable to the point where you can have a whole operating system with only the bare essentials and super fast and efficient memory management. For years Linux has been the number one choice for computationally intensive tasks (over 95% of the world's fastest supercomputers run Linux), and as you can imagine games should/will benefit from this. A cool non technical aspect is that there are formal ways to detect when/if the system abuses or violates your privacy, so you can be sure (at least Debian) is safe. Also, it is DRM free: no activations, no installation limits, no restrictions.