http://www.pixelmator.com/weblog/2011/01/25/pixelmator-grosses-1-million-on-the-mac-app-store/$1,000,000 in 20 days.
Currently I'm seeing this for the top 10 grossing apps:
1. Aperture (Apple) - $80 - This has been really popular, as it's $120 less then the boxed store copy
2. iPhoto (Apple) - $15
3. Pages (Apple) - $20
4. Pixelmator - $30
5. Angry Birds - $5
6. iMovie (Apple) - $15
7. Call of Duty 4: Modern Warfare - $50 - Sadly an Aspyr ripoff, this is $30 on Steam for Windows
8. Keynote (Apple) - $20
9. Numbers (Apple) - $20
10. Civilization IV - $30 - Another Aspyr game, and $20 on Steam for both Mac and Windows.