I don't want it in there because I don't want it to scratch up my iPod...I tried that, but I've seen what the iSkin belt clips have done to the backs of previous generation iPods and I don't want to ruin mine.
It's not a big deal, I just would have preferred it if they made the belt clip a plastic attachment that goes around the silicone shell like the power support cases, instead of making it an integral part of the case.