I use a couple of different tools to capture screenshots and make annotations.

 Gadwin Print Screen is a popular Screenshot tool. The free version doesn't do annotations though.

 http://www.gadwin.com/printscreen/

 I've been using Fireshot for a long time. It works for both Internet Explorer and Firefox. It's a simple extension/add-on to your browser. It will do annotations.

 http://screenshot-program.com/fireshot/

 Lately I've been using Google Chrome as a browser and found a very good screencapture and annotation tool called "Webpage Screenshot". It's not a s fancy as Fireshot, but it does what I need it to do. It's one of the only screen capture tools that will allow you to crop and print your screen very easily. It's my favorite by far.

 https://chrome.google.com/extensions/detail/ckibcdccnfeookdmbahgiakhnjcddpki