I'll give a little more serious answer this time. In my opinion, from the sites you mentioned the only one you would really benefit from is SDBits. They have content that can't be found every where. If you like standard x264 tv and movies, then get an invite. I think it's an excellent site.
For 0day, you already have your bases covered with IPT(my favorite site) and TL. Two of the top 0day sites in my opinion. They both have a shit load content.
As for HD, I would get into Bit-HDTV. It's easy to get into(compared to HDBits), has great content, and very nice staff.
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