My "holy grail" is my Hellboy in Hell #3 cover which I have framed behind Tru Vue UV protective acrylic done by my local frame shop.
All my other Mignola original art pages that I don't have framed I store in these BCW toploaders:
http://www.bcwsupplies.com/cat/12x18-topload-holder
The rest of my original art pages I keep in a portfolio:
http://www.amazon.com/gp/product/B00...=sr_1_1&sr=8-1