I can do anything I need to do on a Linux desktop and the only place I find the need to use another OS is in video editing.
Nearly identical experience except for me it's video editing and Lightroom 4. I use AfterShot Pro on Ubuntu but like the color tools better in Lightroom. That and Netflix, but that's available on Android now.
It's not going to be Linux that kills Windows, Android is the real killer. And as soon as video and photo editing are available, there won't be anyone using Windows at home and Excel is not going to change that.
Bring on the Microsoft astroturfers. That's the surest sign ever of dead company walking.