Coming from Blackberry I would spend some time with the phone on stock getting use to the android interface. Read through the tips and tricks thread:
http://forum.androidcentral.com/general-help-how/31622-getting-started-android-tips-tricks.html
Some apps to get you started:
-Beautiful Widgets.. nice clock and weather widget plus toggle controls.
-Clockr Evolution is another cool looking clock. Displays the time and date In words.
-Launcher Pro Plus with LPI icons.... great for changing the look of your phone and has some great Widgets for your screens. ADW and Go Launcher are some other options.
-Smart Keyboard Pro is a nice alternative to the stock keyboard.
-Angry Birds is a fun and very addictive game
-Coming from BB your probably going to miss having the Bedside mode at night. There's an apps called "Bedside" that works the same but even better then BB's.
That should be enough for you to mess with getting started... read up in the forums and welcome to AC.