This list is mainly targeted at developers using windows computers, however any power user should be able to find a utility or three below which will enhance their computing experience and make things even more enjoyable.
Most of them you will be happy to hear are free, so zero risk to try then out.
Chocolatey – at NetEvolution we are comfortable with both Windows and Linux, installing software with Linux can usually be done with a package called apt-get which retrieves the software you want along with the required dependencies. What is Chocolatey?, its apt-get for windows, working in the same manner as nuget you will find a command line interface for installing all your software currently supported by their repository.
TeraCopy – when you want to speed up copy and paste of files across your filesystem this is just the ticket.
AutoHotKey – something I always try to promote when I see people typing things in repetitively such as email addresses, you can enter a little snippet and AutoHotKey will replace that snippet with a bulk of text you can define in a quick config file.
Paint.net – for most graphical things where what you really need is a good resizer, paint.net will get the job done
7-Zip – forget winzip and winrar etc, this program will handle your archives with ease
Dropbox – can be your free offsite backup for files working in realtime.
Fiddler – An easy, clean, and powerful debugging proxy for checking out HTTP between here and there. It even supports SSL sniffing.