I didn’t play with open frameworks before. So among all tons of ofxAddons, I chose topics that interest me and add ons that may enable me to utilize in my further work.

ofxQualcommAR
http://ofxaddons.com/repos/69
I choose from the Computer Vision catagory. Augmented Reality is a facianating topic for me. It may let developer take advantage of the QualcommAR SDK to develop iPhone application using openframworks.

ofxPostProcessing
https://github.com/neilmendoza/ofxPostProcessing
Very cool effects! It can be good applied to music visualization. 3D colorful particles bloom/convolution.

ofxPd
https://github.com/danomatika/ofxPd
Pure data is very widely used in graphical/sound data programming. ofxPd is incredible useful and easy for these users. One thing to mention is that the documentation is very informative!