I am a new BB user and was wondering what applications you would recommend to get and install on the blackberry and if there are any good links on the forum or other websites that also list must have on the BB 8100... Thank you.

This list will give you an overview of what's available.

3rd Party Application List - BlackBerryFAQ.com

My personal must haves are Pocket Day Pro, Pocket Day Lists, Google Maps, Windows Live Search, Jive Talk and Lex Spell. It might depend on what your needs are.
Edited to add... I almost forgot one of the most important... BBSmart Email Viewer.

thanks for the links!