He's prolific. You're likely using his tools today, and you may not know his name. He's D.J. Jeff Freakin' Key baby, and he's done it again.
Check out his new Screen Ruler. Ya, I know it's been done before by others, but his is in .NET, and it's transparent.
Additionally, if you're not rockin' Snippet Compiler, you're a punk. And I don't mean that in the nice Modern English way. Check out his library of goodness here.
One of the things that I have to give Jeff props on (take a note here, non-UI developers) - his stuff is ALWAYS polished. It's consistant and it's pretty. Not pretty in an overt way, but in a "fits into your life way." The only other developer that has impressed me with their consistant and clean UI is Nick Bradbury.
Note to Freeware/Shareware authors. I will ALWAYS pick the cool transparent app over the opaque one. Maybe that's just me.
(Additionally you have to respect a guy who uses PNG. Also, you can pick Jeff up on ebay cheap.)