Surely if you are looking for screen shots, you'll have seen sophisticated capture programs with a lot of really attractive features. But if you are looking to do a simple screen shot, perhaps these programs are too complex. If you feel this way you should try ZScreen.
ZScreen is a free open source screen capture application for Windows which can take different snapshots of your screen in an easy way.
You can make a full screen shot or capture one of the different regions of the screen.
Zscreen also has the ability to redirect the capture to a photo edition program like Photoshop or Paint.
All this makes ZScreen a good bet and interesting enough for you to capture your screen.