28) Titanium Backup
This powerful backup tool can backup and restore all apps, even protected ones, with their data and Market link. It can also save your phone settings, including your Wi-Fi access point list. Free (suggested donation $5.95).
This app is a full-featured file manager that lets you view and manage the files on your Droid without having to plug it into your computer. You can even use it to backup your Android apps to your SD card. Free.
Dropbox is a client for the Dropbox cloud-sharing file storage service. It makes it easy to get files onto your phone without explicit synching. You can add files to it from any of your computers and then access them from any other computer or phone. Free.
31) K-9 Mail
This open source project has taken Google's standard e-mail client and enhanced it. If you want to do serious, non-Gmail-based e-mail management on your phone, especially using IMAP, K-9 Mail is a must. Free.
If you're a sysadmin, this one's for you. It's a Secure Shell client for Android. Free.
33) RepliGo Reader
A PDF reader that can be used to view Gmail PDF attachments, online PDF documents or PDF files saved to your media card. It features a reading view that reformats pages into a single column, and offers support for embedded fonts, PDF bookmarks and text search. Paid: $4.95.
Use USB Tether or Bluetooth DUN to connect your laptop to the Internet using your Android phone as a modem. You can use your phone to connect via 3G data, Wi-Fi and even VPN. Free and paid. The free version blocks access to secure Web sites. The premium version goes for $23.95.
35) Document Scanner
This app allows you to scan documents with your phone's camera, convert it to PDF and e-mail the PDF to anyone. You can even upload the PDF to Google Docs. Paid: $2.98.