Ubuntu LTS is the best for getting used to Linux. You get more supported software (when companies release a Linux version of software, they don't always provide technical support for all distributions; Ubuntu is generally the most supported). There are also lots of forums where you can get free help with it, like Ask Ubuntu.
If you have an older machine, Xubuntu LTS is an official Ubuntu variation, so it has the same benefits as Ubuntu, and it uses a lightweight desktop that goes easier on older machines.
There are also a lot of Steam games that have Linux versions.
You can't play every game because some only support Windows/Mac, but yes, Steam has a lot of games that have native Linux versions. For those games without Linux versions, the Windows version will sometimes work on Linux.