It seems like every major release these days comes with a special Collector's or Limited Edition (or both).
There are more than a few scheduled for the holiday season, for instance. Which of them are you considering? In general, how often do you spend your hard-earned dollars on these pricier editions?
If you're a collector, I suppose you spring for such sets just because you get a bunch of cool collectible items, like figurines and keychains and decals and stuff like that. It's also nice to look back and say, "Yep, I had that game and I bought the Collector's Edition and I still have all of it!" It's a source of pride for all the collectors out there; those who just return every game they buy probably won't understand what I'm talking about. If you're not a collector, you'd probably have to be a big fan of the franchise to pick up a Collector's or Limited Edition for $70, $80, $90, or even $100 and up.
Then again, what if it's a new IP? What makes you go for the Collector's set then? Just confidence that you'll love the game? Or do you not care as much about the game, and you really love the stuff the publisher has tossed into the Collector's bundle? Back in my day, such things were very rare but if Square had put out Collector's Editions of Final Fantasy games, I would've bought every one. My idea of splurging on that was to buy the game on day one and pick up the strategy guide along with it. That was like a sacred ritual, damnit, and I stuck by it.
These days, though, I just don't care about all the extra goodies. Trinkets have never been my thing, anyway. What about you?