If you work in online advertising & web analytics and regularly execute campaigns for your clients, this one-stop shop comes in handy.

http://www.google.com/agencytoolkit/

This toolkit basically comprises of tools allocated into 4 major categories:

Plan

• Ad planner
• Insights for search
• Blog search
• Hot trends
• Traffic estimator

Create

• Display ad-builder
• Search-based keyword tool
• Campaign optimizer
• Adwords editor
• Adwords API

Place

• Placement tool
• Ad preview tool
• Site & category exclusion tool

Measure

• YouTube insight
• Google analytics
• Conversion optimizer
• Conversion tracking
• Website optimizer
• Webmaster tools