Links from this post:
10 Simple & Useful Reports – http://labs.force.com/10simple
Sales History Advanced Dashboards – http://labs.force.com/SalesHistoryYT
LinkForce – http://labs.force.com/linkforce
Action Plans Custom Objects – http://labs.force.com/apcustom
AppExchange Search for Firefox – http://labs.force.com/searchff
Opportunity Accountability – http://labs.force.com/oa
Cloud Swarm – http://labs.force.com/swarm
Chatter News Alerts – http://labs.force.com/news
Update #1 – http://labs.force.com/update1