I use firefox+oss. it's a package option and the default for www/firefox If you want a better sound experience use netbsd-8 or -current. they have an audio mixer.
mpv has built-in youtube-dl functionality, so it's a bit more convenient to use. streamlink is supposed to be capable of handling some streaming sites that youtube-dl might not. I used to use it for twitch.tv when it was Flash.
