Really you can argue either way, but in my honest opinion, I really don't see any reason not to use a *nix based OS.
One huge thing is security. While viruses/malware/etc. do exist on *nix OS's, there are significantly less than the alternative. It's estimated that there are less than 900 'viruses' for Linux, compared to Windows, which has > 1 million [estimated].
The cost involved in switching to Linux is quite intriguing as well. The operating system itself is entirely free (with some exceptions), and so is all the software you'll need. Since it's entirely open source, you'll find numerous programs to achieve similar tasks, while changing certain features to suit the user. This helps you find the 'perfect' program for the job. The amount of programs out there is absolutely astounding, and is growing daily.
Linux let's you achieve essentially whatever you want when it comes to customization. There are hundreds of unique distributions, and each can be heavily modified in essentially any way to suit your needs. There are thousands of themes out there, and dozens of different window managers, such as Gnome, KDE and XFCE to name a few.
There are a few downsides, however. There is a bit of a learning curve involved, but this is becoming less and less of a problem with easy-to-use distro's such as Ubuntu and Mint. Some tasks can be quite daunting, but as with anything, practice makes perfect. The Terminal is quite difficult to learn to use as a beginner, but will prove to be the most valuable tool you have.
You mention that you game and produce music, so this will play a major role in your decision. Games are somewhat hit-and-miss with Linux, as very few have Linux-native installers. Steam is currently being ported to Linux however, so within the next few years we should be seeing more and more games. WineHQ's AppDB shows the compatibility of certain games and applications running on Wine, so I'd check out the games that you play over there. As for music production, it depends whether you need to use a certain program or not.
There are thousands of arguments either way as to whether or not you should use Windows or Linux. You really just need to look at what you need out of your OS though. I hope this was helpful.
- Jesse