While Apple is offering some modest Black Friday deals on hardware for Black Friday, it usually only amounts to 5-10 percent off. The better deal is a $100 iTunes gift card for $80 (PN D6124LL/A), a not-too-shabby 20 percent off -- like Best Buy is offering.
Everyone with an iPhone or iPod buys stuff from the iTunes Store eventually, and a gift card allows you to put a credit balance on your account that you can redeem for apps, music, movies and books (Best Buy gift cards are redeemable on the U.S. iTunes Store, the iBookstore, the App Store, and the Mac App Store). iTunes gift cards are also great companion gifts for someone getting a new iPad or iPhone for the holidays.
The Best Buy deal is only available through the end of business Friday, November 23, but it's the lowest price that you'll ever see on iTunes content and the credit never expires once added to your iTunes account.
I bought iTunes gift cards from Best Buy when they were 15 percent off recently but those were limited to one unit of the $100 denomination. The current deal doesn't appear to have a maximum (I was able to order quantity 3), so this would be a good time to stock up. (iTunes gift card terms and conditions are here.)
Update: My friend Bill Morlitz mentioned that OfficeMax is offering a slightly better deal: $50 iTunes gift cards for only $35 -- which is $15 or 30% off. The only catch is that you have to pick up the cards in person (in the meatspace) at a bricks and mortar location. You can search the OfficeMax store locator here.