I hope this isn't a duplicate, as I ran a search before posting, but I am surprised this isn't listed yet.
Not really a big deal for iTunes, but isubscribe has me interested, especially as the subscription prices are usually a decent discount on the news stand prices. I know there are also a few organisations around that will get you an extra 5% off isubscribe (although I can't confirm that this will work with gift cards, but I don't see why it wouldn't). So if you're lucky enough to have such an association, it's a good time to stack the discounts :)