Windows 7 comes with an inbuilt screenshot tool, this is one of the best tool for everyday use. Here is how it works and some tricks.
First open the snipping tool by clicking windows button or icon.
Then type Snipping

You will see the program like below

Click the Snipping tool to open it
When the snipping tool opens, you will see that it is ready for taking screen shots.

Using Mouse just drag and select the area you want to take a screen shot of and release the mouse button.
Once you take the screen shot, a new window will display like below with the screenshot

Now, you can directly paste the screen capture in any pastable window or email compose box, using the shortcut keys “Ctrl + Vâ€
If you want to make any edit or highlight the screenshot just use the tools

You can use the pen tool to write or round something to highlight it. You can use the highlighter pen to highlight the content.
Once you done with your editing, Click the copy icon to copy the newly edited screenshot and paste it anywhere you want it.
You can also save this screenshot as an image file for attachment or to save it in file.

You can also choose the pen color of the snipping tool

There is a default border to your screenshots, you can remove it, or change color by going to tools menu, then Options

Snipping tool allows you to take windows screenshot or Rectangular Screenshots, or even Free form screen shots

Just before you take the screenshot choose the option

So finally, you have what you wanted for a quick screen capture and this utility is a great addition to Windows 7 and I think this will be continued and developed in future versions.
I really prefer this Snipping Tool to have the better highlight options like “Paint†or basic features of “Snagitâ€