I use Ubuntu (Linux). About a year or so ago I made the break from using OS/X (I still have a few Macs) but made my Linux box my main PC. Email, Firefox, Arduino, etc. I haven't regretted it.
For a start it is fast and reliable. Secondly you don't have licensing issues like "I see you haven't activated your copy of Windows yet - you have 14 days to do that".
But the really great thing is, a lot of stuff you just expect to pay for on Windows and Macs, you get for nothing on Linux. For example, video transcoding (ffmpeg). Mucking around with PDFs (pdftk). Some things (like Firefox, Audacity, Blender, ffmpeg) are also available on other platforms as well, to be fair.
I haven't had any problems using Arduino on Ubuntu, after maybe an initial hiccup with permissions (covered on this forum and others).
As for VirtualBox, I am running a Windows XP partition to support my Windows programs I wrote a while ago. Compiling a large program is still fast under VirtualBox, so I don't have any complaints there. Plus Wine is a possibility for running Windows programs.
Another consideration is: virus-writers tend to concentrate on Windows. I'm not saying there aren't Linux viruses, but I haven't personally experienced any.
Another great program to look into is rsync - I use that for incremental backups. It's like Time Machine on the Mac (at least, it can be configured to be similar) where you can keep files that were deleted or altered.