Content: Have You Double-dipped? Triple? More?

OK, I confess, as much as I hated having to do it, I have gone back and purchased multiple copies of the same content in different formats.  Normally, I'm against this as a matter of principle since I figure I should not have to pay twice for the same content.  Of course, the move to HD content changes that equation for me since just like the move from VHS to DVD, whether you like it or not, you are getting a higher quality level, which has value.  For VHS, over time, I've replaced everything in my collection with DVD.  For DVD, I'm being more selective since a) for a lot of content the difference from DVD to Blu-ray is negligible or unimportant and b) Blu-ray players are backwards compatible so I can still use my DVDs.  But, there are always certain titles that I'll want the latest and greatest versions of.

Star Wars is an obvious example for me.  I've bought it 4 times already and I'll be buying it a 5th when it eventually comes out on Blu-ray.  Lord of the Rings is another example, I bought the regular and extended versions on DVD, but I'll only be picking up the extended versions on Blu-ray since I find the extended version massively superior to the theatrical release.  Also, I'm a big Firefly fan, so I bought Serenity on DVD, HD-DVD, and Blu-ray.  Interestingly, I don't plan on buying the Firefly series on Blu-ray.  I rented it and found that due to the grainy style of the series, it did not benefit much from the Blu-ray transfer.  So, what are your guilty pleasures that have caused you to double dip for the same content?