[mtgx]

Depends what you're doing. If you like to play with a lot of risky torrents, then Windows Defender may not suffice. I also don't think Windows Defender does a great job at protecting you against infected removable media either. Avira seems to be pretty good at all of that and light weight.

For risky websites, a combination of Chrome, WOT, ublock origin, HTTPS Everywhere and Sandboxie and/or Malwarebytes Anti-Exploit (zero-day protection) should suffice.

Using a Standard (non-Admin) Windows account and being up to date goes without saying.

[cortesoft]

Risky torrents are what VMs are for.