I'm currently using a Crystal Clear Case for my Fuze. It fits snugly, and I'm pretty sure you can't take it off without the right application of explosives or a flathead screwdriver. But, it protects the Fuze incredibly well, although it does get scratched up on its own. I'll take that over scratches on my Fuze anyday!
It's a little difficult to access the microSD card with the case on, and the sync cable does not fully insert into the bottom of the Fuze. However, I'm still able to sync and charge with no problems.
I'd recommend the case for any Fuze owners, but if you're happy with what you're using, I say use it!
All the best.