Winmerge file comparison program
This program will let you compare the contents of two files side-by-side. For binary files such as Word or picture files, it will only be able to tell you whether two files are the same or different.
Filesize: 3.06 MB

Crimson Editor
A source code editor that is quite handy. It supports tab, and remembers what file(s) you had opened.
Filesize: 1.19 MB

How to interpret your statistics
A description of the terms on your statistics page, such as hits vs. visits.
Filesize: 15.9 kB

on-screen ruler
This free ruler can be used vertically and horizontally. You can have multiple copies on the screen at one time. Type F to flip from horizontal to vertical or vice-versa.
Filesize: 322 kB

Pixie--find out the colors on your screen
Pixie will let you pick up the color numbers from any spot on your monitor.
Filesize: 64.7 kB