hi there. a search is always helpful to at least find some existing threads on ipod mini cases.
if you haven't already found it, i'd suggest the www.ipodlounge.com site. there are tons of reviews for accessories for all of the ipod models. in fact, look here for all of the reviews available for ipod accessories (scroll down to get to the ipod mini): http://www.ipodlounge.com/reviews.php
you didn't mention how you'll be using your ipod the most - for exercising, commuting, in your car, etc. that often will help narrow down the type of case you need.