I bought an
InCase leather sleeve for my 60gig 5th gen when I first got it 2 years ago. At first it was only mostly ok, because that plastic circle covering the click wheel didn't work quite as well as advertised--it didn't register my finger along the top third of the wheel at all. But after experimenting--disastrously, since it scratched up the face pretty badly--with a hard, clear plastic case (I can't remember the brand), I wound up going back to the InCase. I eventually took a knife and cut the stitching out of that circle, and removed it. The click wheel was never prone to scratching anyway, and this made it a near-perfect solution for me.
Last weekend I bought a new 160gig Classic. I've never liked the idea of one of those billfold-style cases, and at the time, that was pretty much the only case style yet available for the Classics. So I went to my local Apple store to buy the new iPod, and brought my InCase with me to test. As it happens, the 160gig is almost exactly the same size as the 60 gig 5th gen (which, in turn, is the same size as an 80gig 5.5 gen, so far as I know). It's very slightly thinner, but the end result of that is just that it's easier for me to take it in and out, since the InCase was a really tight fit for my 5th gen.
Since the proportions from old to new (i.e. the screen size, dock location, and control positions) are all the same from 5th gen to 6th, and since the sizing is only very, very slightly different, most cases designed for a 5th gen iPod should work with a Classic, so long as you make sure to get one designed for a 30/40 gig 5th if you've got an 80 gig Classic, or something for a 60/80 gig if you've got a 160 gig. The exception will be any hard cases that snap on or cases designed to fit really, really snuggly, like the various skin-style ones. Those will probably fit loosely or not at all.
