I’ve checked out most of the available Android Market– I go through it almost nightly to see what’s been added. The options are a bit limited, but here’s a good list of apps I’ve found very useful and hopefully you will too.
This application adds NEW power settings to the phone (e.g. how long the screen is on during a call, if device stays on while the keyboard is open, etc.) and allows you to quickly view and change other phone settings depending on different conditions (e.g. turn off the GPS when the battery level drops below 30%, lower the brightness of the screen when on battery power, change the screen timeout if on A/C power, etc.)
It comes with a set of predefined profiles and automatically starts working after installation.
Unless you want to change any of these definitions or use advanced features nothing else has to be done after the program is installed.
StarContact allows you to search for contacts in so many different ways. It really should be built into Android. You’re given a few different search methods along with an on-screen t9 like keyboard which is easy to use without fat-fingering letters.
Useful Switchers is great for quickly turning on/off G3, Wifi, GPS, and all the other commonly toggled items on the G1. There’s a few extras included such as screen brightness and it’ll even give you a little display about your battery and memory usage.
Missed call allows you to actually use that tiny little RGB LED in the ear piece for different types of events. Such as a missed call, incoming SMS or Calendar event. It also allows you to configure custom ringtones for each event and even periodic reminders. Now you don’t have to pick up your phone to see if you have any pending events.
K-9 Mail is a fork of the original email client that ships with Android with a bunch of bug fixes and a number of extra features. The bug fixes along are reason enough to install this app.
This one is for the techies! ConnectBot is a complete SSH Client for Android. ConnectBot allows you to SSH into a linux/solaris or (other unix flavor) machine and remotely control it, read email with mutt/pine/elm or even IRC or MOO.