I've always been a proponent of eating your own dogfood - if you recommend a product you should use it.
Well I've been using evernote for about a month now, and have imported all my One Note notebooks into Evernote - sorry Microsoft, the lack of a Mac client in the end was just too much of pain.
And I've found it really useful, building notebooks for individual projects as well as organising material - but you do need to be systematic and tag documents and note properly - it's no use tagging one document 'sighelm' and another 'silk road', you have got to make the conscious engaged decision to say that 'this clipping is useful for the Sighelm document, and for a more general background on trade and linkages via central asia'.
This actually is good as it makes you think critically about what you are noting and how it will be of use in the future.
And of course you can search for tags across notebooks, as well as dynamically reorganise notebooks, making it easy to reaorganise material as needed.
The other great thing I've found is the iPhone application - you take your phone with you everywhere, meaning that you can take your notes everywhere, and consequently can pull up and find the document that you forgot for the meeting, or indeed at that moment when inspiration strikes - I'm almost convinced enough to buy an iPad ...