I use a purple dot because:
- I'm not fond of my face
- Using fictional characters is tacky (and I don't really have any favorites)
- Using other real people is misleading (and same as above)
- It represents well two things that I know I appreciate: minimalism, and the color purple
- It's unique--there are surprisingly few other geometric shape people out there
- Purple
- Seriously though, it's a nice color