There is a Blackberry Group devoted to nothing but Blackberry in the enterprise:
www.ibbug.org simply because the BB's #1 market is in the enterprise and there is no support site the does just enterprise support.
Aside from the stuff we all use (email, web browsers and games, whatever) the beauty of the Blackberry is in it's ability to use your internal BES server to connect to and admin your windows/unix equipment (3rd party tools) as well as to connect field techs to your dispatch/work order / knowledge base (IBM techs use the BB to open adn close tickets as well as to look up troubleshooting information on their internal site.) Because of their always on hardware they are perfect devices for this.
Also - do not forget that you can control the BES using system policy scripts to further secure the BB in the enterprise - take that PPC and Palm.
Now I have a PPC (5455) and it is an excellent pocket multimedia machine, great for word, excel and powerpoint docs, but really bad for email and not so good for web browsing - and forget about a cell link for wireless - just a pain.
The only thing I would like to see on the BlackBerry is a simple (ListPro) database program.