This changes from person to person, but you can always browse the /r/Android app list. Feel free to add to it or vote for an app. I have listed a few that I use to get you started:
Start with Barcode Scanner - You can use it to install apps with the QR code found through the links to the apps below. An alternative is ShopSavvy which is similar, but will also allow you to search for products via their barcode.
A file manager (ES File Manager, ASTRO or another)
Skype - Replacement keyboard to make typing more efficient (closed beta, search for the .apk). Alternative – Swift key which uses predictive texting
· Mobile Defense - Lose your phone? Use Mobile Defense to find it, lock it, or send alerts. Essential if you're prone to losing things. Non-US users may wish to use either Wheres My Droid (free, local) or WaveSecure (Annual fee, has gps).
· Pandora - For non-US users try Last.FM
· Shazam - (Free 5 tags/month, paid version for unlimited)
· The Weather Channel (or WeatherBug)
· Reddit is Fun - or use Reddit Mobile
· SMS Backup
· Titanium Backup - For Root users, allows the backup of all apps and data to your SD card
· Mint.com - Great for money management if you have an account (US Only)
· Replace your stock Home Screen - Use either ADW.Launcher or LauncherPro
· Rockplayer - Allows you to play almost any media file without converting it
· Appbrain - Great alternative to the Marketplace, and keeps a record of all your apps installed/downloaded (requires login). Easy to install from and browse.
Start with Barcode Scanner - You can use it to install apps with the QR code found through the links to the apps below. An alternative is ShopSavvy which is similar, but will also allow you to search for products via their barcode.
A file manager (ES File Manager, ASTRO or another)
Skype - Replacement keyboard to make typing more efficient (closed beta, search for the .apk). Alternative – Swift key which uses predictive texting
· Mobile Defense - Lose your phone? Use Mobile Defense to find it, lock it, or send alerts. Essential if you're prone to losing things. Non-US users may wish to use either Wheres My Droid (free, local) or WaveSecure (Annual fee, has gps).
· Pandora - For non-US users try Last.FM
· Shazam - (Free 5 tags/month, paid version for unlimited)
· The Weather Channel (or WeatherBug)
· Reddit is Fun - or use Reddit Mobile
· SMS Backup
· Titanium Backup - For Root users, allows the backup of all apps and data to your SD card
· Mint.com - Great for money management if you have an account (US Only)
· Replace your stock Home Screen - Use either ADW.Launcher or LauncherPro
· Rockplayer - Allows you to play almost any media file without converting it
· Appbrain - Great alternative to the Marketplace, and keeps a record of all your apps installed/downloaded (requires login). Easy to install from and browse.