I'm a big fan of DevonThink. I've used the Pro version for two or three years now, to store my web clippings, my own personal Google.
Yesterday, I read through the Evernote review at AppleInsider and it looks like it could be event better. My favorite feature is the bookmarklet that lets you select part of a web page inside Safari, and send to the Evernote server.
I love this combination: a web service to store all this data, and a companion desktop application to ingrate perfectly with my environment.