Good site for streaming movies and shows

I checked the Mega thread, and it does list a bunch of sites. However, it has about a gazillion of them, and I'm not exactly sure if they are safe. Is there something I can do to not risk getting a virus on these sites? My PC is pretty crap as it is.

Also, a lot of people seem to torrent their shows. Is there an advantage to it besides the fact that you get to download the file, or is it because streaming sites are unsafe?