Bulk Rename Utility if you can have an use for this
Classic Shell, unless you like default UI
f.lux <-- heavily recommended
Sandboxie can be useful
SDFormatter if you have SD cards
Always good to have Windows Defender, then have mbam on the side for scanning, ADWCleaner just in case, HitmanPro (need paid version to remove threats but it can detect them regardless and show you them), Junkware Removal Tool, RogueKiller and USBfix.
If you don't download random crap all the time it's probably not really needed but doesn't hurt to run them every once in a while.
This should cover mostly anything you'd ever really need unless you really download random unsafe crap and get really bad viruses lol.
Never install more than 1 active scanner at the same time, they tend to interfere with each other and do more harm than good. If you have either Avast or Kapersky set up to scan only on demand, then that's fine, but don't let them both offer real-time protection at the same time. Windows Defender isn't an issue for this, as it disables itself when it detects you have any other passive virus scanner installed.
Also, for an easy way to install some useful programs on a new system, check out http://www.ninite.com.
And if you really want to waste space and/or like rhythm games, get the full Lunatic Rave 2 BMS package, it's a 50GB zip containing 70GB of songs
From back when I still use Windows:
Malwarebytes Anti Malware
Steam if you need it
Deluge (Transmission is about to get Windows builds so use that)