First of all I download blackberry app world, which keeps apps downloaded via them up to date.
I installed "forward and edit" which is what it does. Perfect obviously for forwarding emails, but being able to edit the email. (Should have been a standard function on BB, but its not).
"Worldmate Gold" which has a free edition, but I got the paid one. It keeps track of your travel, rentals, hotels, etc. Currency converter, airport, and airlines contact lists, flight status and search, hotel bookings...
Kayak does about the same, but ever so often it blocks, and I need to reinstall.