How Much Space Do You Save with DNG?

I've been researching all sorts of fun photography trivia for my upcoming book, Digital Photography Companion, and one that I thought you'd enjoy is this nifty chart that compares Raw, DNG, and Jpeg file sizes on a handful of DSLRs.

The major take-away is that you only save file space with DNGs (over the original Raw files) if you don't include a Jpeg preview (or obviously embed the Raw file in the DNG). But if you go sans Jpeg, you can save a couple MBs per shot on a 12 MP camera. Is it worth the extra work to convert? Only your hard drive knows for sure...