I was using Evernote for about 2 years for GTD. My setup was following:
Noteboks (only two):
Rest of the work was done by tags:
GTD status: #Next, #Someday, #Scheduled, #Waiting, #Reference
Context: @Home, @Work, @Computer etc.
Project: +House renovation, +Films to watch, +Buy new car, +Car maintenance, etc.
By starting each group of tags with special character, I was able to easily manage the tags.
For my convenience I have created few saved searches and added it to shortcuts.
The system works quite well, however I was not satisfied with the application itself. So finally basing on my experience with implementation of GTD on Evernote I have created an Android application called "GTD Simple". I am still working on adding new features to it, however it is available on Google Play, if you want to test it (it's free and with no ads).