After a California woman was turned away at the Apple store when she tried to buy an iPad with cash this week, news outlets have been following the story pretty closely. Apple's credit-or-debit-only policy exists to prevent people from purchasing iPads in bulk and selling them overseas for a profit. After some serious public outcry (including a Facebook page dedicated to the cause), Apple changed its policy, allowing anyone to purchase an iPad with cash.
Beyond that Apple offered Diane Campbell, the woman who originally tried to make the cash purchase, a free iPad for her trouble. If you do choose to pay for your iPad with cash, you'll have to activate your Apple account at the store at the time of purchase; a safety measure to ensure the two-iPads-per-customer rule is maintained.