Malwarebytes is very good. It's not your typical anti-virus program, as it's an anti-malware program, but it's a lot better than whatever most people install (avast, kaspersky etc).
As for the kindle, as long as you just read and download e-books from the amazon store you'll be fine, no worrying about viruses needed.
Netflix, for here, is amazing, but it has a pretty limited catalogue. The streaming thing aside from netflix is good in theory, but it ends up being a pain in the ass most of the time. The slow internet in Argentina combined with the fact that all the streaming links go down within days can end up being very annoying.
Torrenting (once you get used to it) is very easy. Download uTorrent from their website, visit a site like torrentz.eu and search for the show/episode you want (look for the results that have a green checkmark behind them), download the .torrent file, and just click it once it has downloaded and it will automatically do the rest, and download the episode to your PC. After you're done watching, you can just delete the file and done. The quality of this is ALOT better, and you don't have to wait for the episode to buffer.