Hey!
I always used to simply plaster all my devices with invisible protectors and the like, but often the cheaper ones make your phone, iPod, or PDA look tatty.
Has anyone used Decalgirl.com ? They sell a huge range of very attractive 'decals' or skins which cover the back and front of your Touch Diamond (and many other devices), protecting it from light scratches, fingerprints and smudges. They're not invisible, they're patterned and they look amazing (though there is a 'solid state black' one for those who prefer it). The quality is fantastic, and there is absolutely no sticky residue.
It doesn't come with a screen protector so if you can find a good one of those you're set. To me, it's just a great way to protect the rest of the body while adding even more style. They also come with a matching wallpaper

They're also really cheap but high quality.
Check it out :
http://www.decalgirl.com/browse.cfm/2,293.htm