Internal vs External Frame Backpacks

There is much debate over what is the right back pack to choose.
It all depends on what you are going to do.

Internal frame backpacks are become more popular, but are more expensive.
many of the Internal Frame Packs (IFP) are one long bag, that you have dig through to get stuff out of the bottom.
External Frame Packs (EFP) allow you carry extra gear out side the back.
They can support more weight, and are sometimes lighter then IFP.

Here are some links to learn more:

https://www.google.com/search?hl=en&site=imghp&tbm=isch&source=hp&biw=1366&bih=598&q=backpacks&oq=backpacks&gs_l=img.3..0l10.3488.5851.0.6109.9.7.0.2.2.0.157.768.5j2.7.0....0...1ac.1.26.img..1.8.624.a1g3EKVvFEs#hl=en&q=internal+vs+external+frame+backpacks&tbm=isch

http://www.outdoorgearlab.com/Sleeping-Pad-Reviews

http://boyslife.org/outdoors/askgearguy/3239/internal-or-external-frame-on-backpack/

http://www.youtube.com/watch?v=uh7wQT22Ixs