I just bought a bold 9700 about two weeks ago, and I like it a lot so far. I'm coming from an iPhone 3g. I need some great apps and your favorite uses for the blackberry so that I become just as hooked as all of you!
My favorite apps are BerryBuzz, BerryWeather, and Pandora. Beejive is pretty cool too. I tried it out but the only use I had for it was FB chat. It's great if you have multiple IM type accounts (AIM, Windows Messenger, etc). I can't really say I have a favorite use for it other than the norm...push email (I don't check my personal email accounts since I get it on my BB), facebook, twitter, BBM, and web browsing. I use the actual phone less than those other things
quicklaunch.....awesome app with a windows popup/ startmenu
ewallet- with desktop client allows storing password info, etc.
laterdudepro- allows you to schedule reminders at a later date, notes, tasks, contacts, emails, ,etc.
Iheartradio for me. Vuclip web video search for videos, uses YouTube and other sources, and auto converts videos that won't play on YouTube. Also can stream videos via Wi-Fi.