Well I'll disagree. I have a Moshi iGlaze on my Air, and have cases on all my previous Macbooks, and with a regular cleaning i never saw dings, scratches or dents. So not everyone faces this issue, some people have more of a tidy lifestyle than others, so no, not everyone faces this issue.
As for the OP, get the Moshi iGlaze, it is a great case, there's a nice speck one too!