For anyone looking for a cheap but serviceable case that protects everything well, I've been using this one I picked up on ebay
The camera lens is well covered, so that you can lay it down face up - and the lip on the front of the case is proud enough to protect the screen if you put it face down.
I'll try to get some pics when I get my Desire Z camera working on the Sense 4 ROM
The plastic looks and feels a bit cheap, and the white one I got is starting to get a little grubby, but it feels like it will put up with a lot of abuse.
The power button and volume buttons are covered by the case rather than cut outs, which should help keep dust out, and I've had no real problems with the case buttons responding to a firm touch.
It's also not too bulky imo, and still lets some of the design of the phone show through. The clear back shows off the logo nicely too.
It's no Otterbox I'm sure, but for 3.49 including a sock I don't think you can go too wrong...
Always code as if the guy who ends up maintaining your code will be a violent psychopath who knows where you live. ~Martin Golding