I take it you don't do any scientific computing?
You know what? I don't. I'm mostly involved in psuedoscience myself.
For me, and many average computer users, the lack of MS Office becomes a major problem with a Linux desktop. OpenOffice might be similar, but it's not the same. Google Apps is handy, but it's about equivalent with MS Works.
I can understand the appeal of Linux, the ability to really tinker with things etc. but most of us just want to have the damned thing do what we want with the minimum of fuss.
I'm really not against Linux per se. For average joe users doing very basic stuff, it's fantastic. My mum had a PC running Debian for years. It did what she wanted and didn't pack up like Windows machine would. However, if she were actually trying to get work done on it, and had prior experience of MS Office (she'd always had a secretary), she'd have lobbed it out the window.