Wired.com have an article about Ubuntu and its usefullness for the non-geeks out there.
Read it here
Can Ubuntu completely replace Windows or Mac OS X?
Probably not. It doesn't work perfectly out of the box. And even if you do get it working smoothly, you may miss industry-standard professional programs, such as Photoshop and Adobe InDesign, or entertainment software such as iTunes and video games. The best strategy for most people is to run Ubuntu on the side as a hobby, gradually learning its intricacies. “Try things out before you really need to do them, so you avoid panic,” said Grant.