I like people to be able to handle my jewellery and try it on (generally I find if they pick it up it sells itself).I tried putting necklaces on cards but personally didn't find it worked for my varied styles of jewellery so now I add a tag (here's a picture http://www.flickr.com/photos/surfingcatclay/5084560605/in/photostream)
I usually have some of them pinned onto display boards and some on busts (made myself using a pattern from http://www.home-jewelry-business-success-tips.com/necklace-display.html - I tie the string with a bow and then store them flat. I made them using fairly thick card and they have lasted over a year so far. There is lots of other great advice about selling jewellery on the same website too).
Using a rack and cards would probably give you more efficient use of space if you have a lot to display. Like your shutter idea.
Good luck working out what's best for you, it's amazing the different solutions people find.