Every collector has "rules" that the use to define the bounds of their collecting habbits.
For me I collect only NTSC Xbox 360 CEs, and PS3 exclusive US CE releases.
But we all also have a few titles that fall out side the bounds of our "rules".
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For me these are my rule breakers:
Dead Rising (SteelBook Edition) (Xbox 360) [PAL] - I'm a fan of the series, and a sucker for SteelBooks. I kind of always wanted this release since the US never got a CE for the first Dead Rising... when I saw a member had one up for sale at a reasonable price so I couldn't help myself!
Bayonetta Climax Edition (Xbox 360) [PAL] (Aus) - I really liked the Scarborough Fair replica that came with Australian Pre-Orders for the Climax edition so I went out of my way to buy one... After the fact it seemed silly that I didn't have the Climax Edition to go with it so I decided to pick up a matching Australian variation of the Climax Edition too.
Fun fact: I've never played Bayonetta
Metal Gear Solid Ultimate HD Collection (Zavvi World Exclusive) - Despite my not collecting European releases I couldn't help myself with this one... the Allure of a SteelBook and a numbered release to boot, of such a wildly popular franchise, I'd be a fool not to pick one up!
Fun fact: I HATE the Metal Gear Series

(it mostly has to do with the fact that I find the camera controls infuriating)
So what releases did you buy that broke your rules, and why?...