One of my most used programs is TechSmith SnagIt.  TechSmith makes great tools, we use Camtasia Studio to generate 'online demo videos' for our AJAX toolkit SSS Research.  (And TechSmith started in the town where I grew up, and (I think) my brother went to East Lansing High School with one of the TechSmith team.)  All reasons to love them, sure, but I was using SnagIt before I found out any of those degrees of separation!

I use SnagIt daily.  Working with computers, I'm the defacto tech support for my friends and family.  I used to answer support requests with "On the Tools | Options | Mail Format tab, choose the 'Signatures'  button..."  Now, when I get asked a question,  I just email back a few screen captures highlighting what options need to be modified.  My friends are happy because the screen captures are easier to follow than the menu hierarchy, and I'm happy because screen captures are quicker to make -- just grab a screen, and draw an arrow to the button.

I also use SnagIt as my PDF generator.  Adobe Acrobat is the closest thing to a virus I know, and I won't install it on my computer.  SnagIt, however, can "save as" PDF, and with the latest release, they can even be installed as a print driver.  So, if I need to create a PDF report for somebody, I "print to SnagIt, and then Save As PDF."

SnagIt can also upload straight to Flickr, which is pretty handy for blog posting.

Blurring the background of images is pretty easy to accomplish, but I've always wanted to 'blur the foreground' of my capture.  This would allow me to blur out names or such before I post to the blog.  (SnagIt doesn't implement the 'invert selection' (ctrl-shift-I) that I'm so used to with PhotoShop, it seems obvious to me, so I'm sure it is on the list to do).

I finally found how to blur the selection.  It's not the most discoverable feature to find (I've been wanting to use this feature for months) I will say that it is already in there.  Seeing as I can't use SnagIt to make a screen capture, I'll have to write out what the options are.

Get your screen capture into the SnagIt Capture Preview, highlight the region you want to blur, and choose 'Effects | Image Processing | Average Blur."  Choose the "blur amount" and your done.

Checkout SnagIt, read the reviews, if you dismissed this as YASC (Yet Another Screen Capture) program, look again, it's a surprisingly useful product.  You will find yourself using more often than you thought.