I think it depends how experienced you are. Are you using public or private trackers? There's a big difference imo.
If you're downloading cracked software and such things, I don't think there's a big difference. Almost every crack will be caught by avast (free) or eset (paid)
Another thing, that is worth mentioning that I had best experience with kaspersky. It clearly says with is a virus and what is a "harmless" crack. It won't automatically delete/quarantine things like eset, norton..
If you're downloading movies, I don't think there is no need for any AV. You must be reeeaal noob to get infected just by downloading a movie.
But again: read the first sentence
