For screen capture, I recommend these apps:

The best screen capture (IMO) - SnagIt: http://www.techsmith.com/snagit.asp
(You can't get too much better than the full Camtasia Studio but it's pricey. Adobe has Captivate but that's even more expensive...)

DebugMode's Wink if you want to delve into tutorial creation (for free): http://www.debugmode.com/wink/

Another good one for purchase UltraSnap Pro: http://www.mediachance.com/ultrasnap/index.html
(MediaChance has other good tools as well...)

I just love all of Iconico's tools (Calipers, Magnifier, ColorPic, etc.): http://www.iconico.com/


-Will