Speedfan..

Still the best utility to monitor internal temperatures, and it includes a useful SMART function too..

http://www.almico.com/sfdownload.php

Should I Remove It..

Not something that you would have to run too often, but it can pick up on some interesting stuff that you may not have been aware was running in the background..

http://www.shouldiremoveit.com/index.aspx

Treesize..

Sometimes, it is useful to see where all of the HDD/SSD space is going. This will show you. .

http://www.jam-software.com/freeware/index.shtml

 IMGBurn..

A utility which allows the conversion of an ISO file into a bootable CD/DVD for use when installing an operating system..

http://www.majorgeeks.com/files/details/imgburn.html

Wireless signal analyzer..

If you live in an apartment block and/or are surrounded by them, it is useful to know which Wi-fi channels are being used by the strongest signals in your vicinity, such that you can distance yourself from them. This utility will help you make a leaned choice.. 🙂

http://www.ampedwireless.com/wifianalytics/