I collect the Muppet Busts. I just started with them, so right now I only have five. That's 1/4 of the whole collection.
Also Hard Rock, my friend, I have to tell you, you think they cost some money on Ebay, dude they were way more money when they frist came out. They were like 45-60 bucks each.
Also I've noticed that Beaker and Fozzie seem to be the hardest ones to get.