I am currently using a flip case for my desire which is built for nexus and it fits my Desire perfectly. It's not loose at all and all the buttons are exposed, not obscured by the plastic inner case that holds the phone. It is having a faux leather type material, which seems quite nice and the stitching is also good quality:). It's padded on the outside flip part, and a rougher faux leather on the inside however it is not enough to scratch the screen.
But the only problem is it uses a magnet to secure the strap, which messes with the phone. The compass on the Tricorder app wouldn't work, and the GPS on google maps was a little thrown off. I'll probably have to cut the magnet out. To me it is a decent case and has good build quality, despite being under £5. There are even lots of £20+ cases in the market that are of equal if not worse quality. The magnet is an issue but as far as I can tell it doesn't interfere with the rest of the phone, only the gps and whatever sensor the compass apps use.
HTC Desire Case