There are many pragmatic reasons for a non-geek to switch to linux.
1. Package managers and the ease of installing free software e.g. easy to search for without entering commercial sites laden with ads and sometimes trojans, no EULA type nag screens.
2. Better jukebox software. Amarok can easily rip music off of ipods, which is widely appreciated by non-geeks (some people have their entire music collection trapped on a single ipod, and when linux can make that ipod send its songs to the outside world they become believers).
3. Better video playback software. Even though mplayer and vlc are ported to Mac OS and MS Windows, they work best on linux e.g. smoother playback and response to controls, better OS integration, current feature set closer to developer feature set, etc.
4. Best videogame console emulators. Since many emulators are open source (with notable exceptions) they are primarily developed as linux apps with windows ports that lag behind in features. Also, WINE really does run many recently popular games.
5. Superior performance in all things hard drive related, linux is better at reading, writing, and not going into retarded fits of swapping data to the drive like MS Windows is so fond of doing.
6. Better network security, and better multi-user PC security.
7. More aesthetically and functionally customizable.
What are the current aspects which prevent linux from achieving its critical_point of adoption on the desktop this year?
a. Lack of familiarity with the OS and applications.
b. (really a corollary of 1) Some favorite applications are not availible.
The solution to both (a) and (b) is marketing, which linux does not get very much of and hence the perpetual delay of its year.