Question: Yes, I am aware one is a framework and the other a CMS.

However, I am a one man team that develops projects/websites for myself and I have a limited amount of time to get these projects off the ground, so speed is crucial.

Basically I am looking for the easiest and fastest method for creating web apps without being limited on features.

Would it be best/fastest to learn Codeigniter or to build off of Wordpress and develop my own themes/plugins? Possibly another option that would be more viable?

I deal a lot with video/photo media and high traffic websites.

Thanks!

Answer: 
I would suggest using CodeIgniter. The logic is simple, and it doesn't really have limitations, unlike WordPress. WordPress is designed for blogs, and if you are looking for flexibility, I would go with CodeIgniter.

CodeIgniter has one of the best documentation available as well. <http://codeigniter.com/user_guide/index.html>

If you are looking to learn CodeIgniter, NetTuts has some great tutorials, with different levels.
<http://net.tutsplus.com/articles/news/codeigniter-from-scratch-day-1/>

There are some nifty CodeIgniter libraries that can get you head start on your projects:

* <https://github.com/benedmunds/CodeIgniter-Ion-Auth> - Ion Auth, CodeIgniter Authentication Library
* <http://www.kaydoo.co.uk/projects/backendpro> - Backend Pro, designed to build admin side of your application.

If you are looking for CodeIgniter based blog/CMS, I would also suggest PyroCMS, one of the best I've used.
<http://pyrocms.com/>

CodeIgniter also has a great image manipulation library built in, so you won't have to learn too much about generic PHP image libraries.
<http://codeigniter.com/user_guide/libraries/image_lib.html>
If what you develop is web applications, especially for high-traffic sites, then why not to also consider Doctrine? It is a really good framework for developing webapps. Regarding WordPress - if what you need is mostly webapps with extensive user interaction and complex data structures - WP can't handle that efficiently due to lack of ORM and MVC pattern support (there are a couple of workarounds, but anyway). 

And if you're open to learn new languages - also consider learning RubyOnRails and Django - both are awesome platforms, documented well and having awesome communities.