Here's another knife designed to make dealing with blister pack plastic packaging easier: the "Plastic Surgeon." It's nine bucks, plus shipping, although you can get similar products like the Open X for around the same price. (And I've seen the Open X sold in stores.)
You know what would be better? If retailers would just stop asking for companies to sell items in blister packs. I know they think it helps prevent theft. Maybe it does. But as a reformed teenage shoplifter (at least the teenaged part), I can assure you that thieves are only too happy to carry these sorts of knives with them, the better to liberate the item from its packaging in a dark corner.
Product Page [PlasticSurgeonOpener.com]