We discussed over Christmas starting a toy related thread over here for folks to share the glory of toy collections.
Personally, I collected Star Wars until the prequels ended but those are all in storage now thanks to a downsizing in apartment space. I do still buy the occasional Lego kit, pop figure or action figure - but this Christmas I got the collecting bug again.
So far I've got just Wave 1, but I'm starting to buy the new Masters of the Universe Origins line. They just stopped being Walmart exclusive and if my birthday weren't coming up and I'd get in trouble, I'd have grabbed them all by now.