Listen everyone! If you have the LaCie Mobile Disk 320GB hard drive, forget the "Caselogic Small Hard Drive Case" which everyone else seems to buy....get this one! The size is PERFECT for the LaCie, the device fits nice and snug, and there's still room for the cable! The case is pretty sturdy, too. I'm not going to test it of course but it looks like it'll do the job of protecting the drive whilst it's in my bag. There's an elastic strap inside and this secures the drive very well too. And the seller.....top marks again, got it delivered next day!
I did some shopping around and my experience is you'll struggle to find a portable hard drive case this small, it's the smallest one I could find. It goes without saying, check the dimensions of the case and your hard drive before buying, but I reckon that if you've got one of the new generation of very small, portable external HDs, this is the best case for the job.