I like the Piel case
I had the Piel for my original iPhone. I had the one with a flat front with magnetic closure. I liked it so much that I ordered the same case when I got my iPhone3G. That was two years ago.
I just received my iPhone4 and would definitely order another if they come out with the same design (i.e., without the tab the wraps around the bottom of the phone to close.) One of the earlier posts is right, though...the flap usually was in the way when I wanted to use the camera...I usually ended up just sliding the phone out of the case when I wanted to snap a pic.
The one for my 3G is still in really good shape....good enough to put it up for sale on eBay.....not pristine, but definitely in good used condition.
I guess that makes a pretty good endorsement, as I look back at what I just wrote !!
And, for the skeptics, I am in no way associated with Piel.