Some options for those not wedded to OneNote or EverNote:

I mentioned a couple of approaches I use for ad-hoc info gathering and easy retrieval in this post which are a private forum and my own built home page. Like many, I also use a few text files for daily use stuff, which open in tabs when I launch my text editor.

I just saw a couple of other programs, which I haven't tried:

For Windows: CintaNotes Free or $39
Looks slick and full-featured in the paid version.
Quote Originally Posted by CintaNotes
mark the text that you want to store and press Ctrl+F12. And voilą! CintaNotes' main window pops up, focused on the new note with the clipped text, along with the source URL of the website or the local storage path of your document.
Quote Originally Posted by CintaNotes
Pressing Ctrl+Enter or the middle mouse button will paste the currently selected note (or notes) into the Windows application that was running immediately prior to opening CintaNotes.
Quote Originally Posted by CintaNotes
tags can be organized into a hierarchic structure. Such tree-like structure is very useful for creating various taxonomies. Creating tag hierarchy is simple. Just create tags with forward slashes in their names, for example it/gadgets/ipad or Projects/MyProj1.
For Mac: Notational Velocity
Different approach, interesting.
Quote Originally Posted by NV
Notational Velocity's window was designed for keyboard input above all else, and thus has no buttons.
Modeless Operation - Searching for notes is not a separate action; rather, it is the primary interface.
The same area is used both for creating notes and searching.
There is no manual "saving" in Notational Velocity; all modifications take effect immediately.