I've had an iVolution Top case on my 3G for about 10 months and it is by far the best case I've ever seen. True it's pricey but well worth the money. You can see it here:
http://www.everythingicafe.com/forum...tml#post346691
It looks as good now as it did then. The only thing I'd warn you about is that the darker color dyed leather tends to show rub marks. I don't think the black does because mine doesn't show any but my wife's is a dark purple and the color along the edges is beginning to wear. It doesn't look bad, it kind of adds some character to it. Also, the screen cover has a lip on the top that hooks over the phone, across the SIM card slot and it has held its shape just fine which makes it stay closed just like it was new.
The leather hinge that connects the screen cover to the rest of the case is holding up very well but the orange stripe in it is beginning to fade but just slightly. I don't have a belt clip for mine so it slides in my pocket very nicely. About the only thing I wish were different is that I have to keep the top open to charge it. There isn't a hole in the top hinge for the cable so you have to open the screen cover to charge it. You also can't put it in any docks without taking the phone out of the case.
If you're considering spending the money for one, you definitely won't be disappointed.