I would look into two things, if I were you;
Getting a bluetooth keyboard (I have the Freedom2), and also getting a program that specializes in what you are trying to accomplish. Maybe ACT! has a mobile version?
Storing the data is not a problem. The BB will be fine for managing contacts and keeping short notes. But longer emails or summary narratives will take you a long time to thumb type and you will eventually lose your mind.
You will also need a desktop PC or other PC to act as the chief repository for data / synchronization.