Not all refurbished products are created equal. The very definition can differ depending on what the product is and who's doing the refurbishing.
For example, I once bought a small, refurbished HDTV that had a broken stand, scuffed bezel, and barely there packaging. Bleh.
However, when it comes to Apple products, I see no reason to choose anything but refurbs. I say this not as a gushing Apple fanboy, but rather as someone who thinks most Apple hardware is overpriced--and sees refurbs as a rare opportunity to get it for less.
Likewise, the refurbished 32GB iPad 2 Wi-Fi is $499, a savings of $100. You can also score 3G models from AT&T or Verizon at similar savings. And shipping is free.
Now let's talk MacBook Air. The current-gen model starts at $999, but you can save a whopping $150 by opting for its refurbished counterpart. And last year's (well, 2010's) Air is available for as little as $699. That's downright reasonable.
Sounds great, right? Sure, but what's the catch? What do you give up by opting for refurbished Apple gear?
Apple's refurbs come with a new outer shell and new battery, meaning you get same-as-new appearance and performance. Better still, you get the same one-year warranty Apple extends to new hardware. There is literally no downside.
But there is one small cosmetic difference: refurbs come in nondescript cardboard boxes, not the fancy white ones afforded to new gear. Big whoop, if you ask me.
Apple's refurb offerings and inventory change over time, so you can't always get what you want. But I think it's the only logical place to start your shopping. I've purchased refurbished iPhones, iPods, and iPads, and every one of them arrived in perfect, like-new condition. Consequently, when it comes to Apple gear, I can't see any reason to pay extra for the new stuff.