I've gotta second this, command-t is probably my single favorite plugin. I tried using FuzzyFinder way back when, but it was just a little too quirky to be useful. This blows FuzzyFinder (and even fuzzyfinder_textmate) out of the water.
Navigating you project in this way feels a lot quicker than actually browsing the hierarchy with something like NERDTree. Don't worry about where things actually are, just type some junk and the file you want will almost always come to the top.
I can _highly_ recommend this plugin, even if it's a bit harder to install than most other Vim plugins.
Check out https://wincent.com/products/command-t and http://amix.dk/blog/post/19501#Command-T-for-Vim-an-awesome-...