K - here's mine.
AutoStandBy - Can get 2.5 days out of my battery with medium to heavy use. It is problaby the most Efficent app I have.
BBAlerts - An Awesome app. No need to turn on or unsuspend my BB just to see if I have msgs. I can tell just by looking at the Color of the LED if I have an E-Mail (and from certian people), an SMS, MMS, Calendar Alert, Task Alert, etc.
Windows Live Search Mobile - A great free app from MS. I'm not big on Windows anything, but this app is quick to find anything I need using my gps. I can then call it, drive to it, add it to my contacts and more.
Other than that, I use the standard BlackBerry Apps.