DataViz lets you create and edit Word and Excel files and PowerPoint presentations, and view PDF documents. A free version lets you view Word and Excel documents.
This app, by Burrotech, lets you use your phone's camera to scan contracts, receipts, and other documents as full-color PDFs and e-mail them to your desktop.
A must-have when entertaining clients, Zagat has ratings for 40,000 restaurants, nightspots, hotels, and shops. Use your phone's GPS to find nearby options or browse Top 10 lists for various cities.
Seesmic neatly groups all your Twitter timelines in one screen. The coolest feature: the ability to customize alerts, so you will be notified only when specific tweets are posted.