1. WP-DB-Backup
http://wordpress.org/extend/plugins/wp-db-backup/

2. Akismet
Spam filter for you comments. Now a monthly fee and need a api key
http://wordpress.org/extend/plugins/akismet

3. All in One SEO Pack
On one of your posts, you should see a new field for description and keywords
http://wordpress.org/extend/plugins/all-in-one-seo-pack/

4. WPTouch
Created to make site easy to view on the iPhone, Android, etc
http://wordpress.org/extend/plugins/wptouch

5. wp-Typpography
Use proper typorgaphy, for ampersand etc. You get a fancy &, etc
http://wordpress.org/extend/plugins/wp-typography/

6. WordPress.com Stats
Feature that's missing when move from cloud based to self hosting
http://wordpress.org/extend/plugins/stats/

7. Contact Form 7
http://wordpress.org/extend/plugins/contact-form-7/


8. FancyBox for WrodPress
Fancy pop up box for pics
http://wordpress.org/extend/plugins/fancybox-for-wordpress/

9. Sharedaddy
Add Share buttons to page, missing on self hosted sites
http://wordpress.org/extend/plugins/Sharedaddy/

10. WP-PageNavi
Add pagination to bottom of your pages
http://wordpress.org/extend/plugins/wp-pagenavi/