1. Antivirus for Wordpress

2. Digg/bury blog comments like Digg.com

3. Spell, Style and Grammer check with After the Deadline

4. Detect Adblocker and display alternative

5. Insert anything into Wordpress Blog Post

6. Improved web typography in WordPress – WP-typography

7. Improve page load time

8. Custom ‘Read More’ and Thumbnailed Recent Posts

9. Add shadows to a range of objects

10. Implement E-Commerce Shopping Cart

11. Add private notes to Wordpress blog post

12. Allow users to upload and share photos at ease

13. Paginated Comments

14. Manage who sees the ads

15. Display Thumbnails for Related Post

Read more about the above things and another 15 more here