I dont wanna be an *** here, but I feel the need to defend Pirate Bay here. The only reason you got trojans from there is because of your own faults. Mainly not checking the comments on files, not sticking to popular files, and of course, lack of antivirus software which would easily combat such threats.
--
As far as downloading from youtube, I suggest:
+
Orbit (
http://www.orbitdownloader.com/)
and either
+ VLC (
http://www.videolan.org/vlc/)
or
+ FLV Player (
http://www.download.com/FLV-Player/3000-2139_4-10467081.html)
Use
Orbit's Grab++ feature to download the files as .flv's and then
VLC or
FLV Player to play them back. You could also try to find something to convert the FLVs to more standard formats. VLC is probably better just because it will play just about any video file and format, not just FLVs.
But azem's method might be alot easier, lol