Kreg K4 Pocket Hole Jig
Although this isn't a power tool I have to mention this awesome tool, if your a beginner woodworker like me and woodworking joinery scares you this is a fantastic tool.
The jig basically takes all the angles out of joining multiple pieces of wood together the jig is basically a clamping device that sets up all the wood to receive pocket holes that you screw self tapping screws into the pocket holes and build anything from a bookcase to a my most recent project a Cedar Cooler Box for which you can see on my link below
I also built a mounting platform for the jig that contains a drawer and you can find this project in the below link
To find out more about the K4 jig please visit the below site for jig details and a video detailing what the jig can do.