There is currently 50% off TreeDB Notetaking software.
I have been using this product for years and it is fantastic, and it is very rarely this price. Last time I recall was around this time last year.
The most common use of it is for advanced note organization.
Note that it only works on Windows - and a portable version exists. Some cool features in Pro includes encryption. Full comparison between free and Pro can be viewed at: http://www.mytreedb.com/free_vs_pro.html
Unsure when the deal ends.
I know we are not supposed to do this but is it possible to buy the personal license and install in more than 2 PCs? Does the software check how many copies are concurrently running?