1. Youmail: The best voicemail app to date. You can create over 200 customized "answering machines", request email notifications for missed calls, get voicemails sent you as an mp3 email, and has a caller block list.

2. Where's My Phone: Helps you locate your lost Blackberry. You can send an email to your phone with a "key phrase" subject line. When the unique subject line appears the app recognizes it and shuts your phone down. It then gives off a police siren and blinks red and black. Hot! If stolen or lost, it prompts the finder to call an emergency number (that you list during setup).

3. Sensobi: This is the application I use instead of the standard address book. It "ranks" your contacts based on how often you communicate with them and notifies you to call/text/email people falling "off your radar". It is perfect for customer/client relationship managers. You should never just call people when you want something. This helps you to manage that philosophy.

4. foursquare: The newest social phenomenon that premiered in SxSW 2007. It's all about geo-tagging and checking into venues. When you check in often, you get to socialize with past visitors and you win "badges". Its a socialite virtual world.

5. Google Sync: The lifeline. Syncs calendar and contact info from your gmail account to your phone. If you know me--then you know that google calendar runs my life. It's important to have every contact you interact with on your desktop to be available in your blackberry address book.