Battery Monitor Widget
and System Tuner
are two utilities from the same publisher that I find quite useful for keeping track of what my phone is doing.
allows you to do a lot of things you normally have to push the physical buttons for using only the screen to help the phone last longer.
has lots of GPS-related functions. GPS Test
is good for troubleshooting your GPS system if you're having trouble getting it to work right. It also has some good functions but, while better for troubleshooting, doesn't do as much as GPS Essentials.
is a good task management app that syncs with your Google Tasks for those who want something to help them manage their time better. There are several others as well, but this is the one I settled on.
is good for the musical among us. It's a richly-featured app for tuning instruments.
The Coupons App
and YP Local Search
are good for finding coupons, local restaurants, gas prices, etc.
finds all Wifi signals in range and helps you connect to Wifi networks.
SMS Backup and Restore
is good for backing up your text messages so you don't lose them with OS updates/crashes/etc. It can also be used to transfer your messages to a new phone.