The iPad is not very durable at all as some of the previous posters have stated! I dropped a bowling ball on my iPad and it left a pretty big dent! I have a MBP as well which I dropped a dumbbell on and it left a dent too!
In all seriousness, I have owned MBP's since 2006 they have fallen off beds or couches numerous times and besides some small unnoticeable unnoticeable scuff marks on the machines I've only had 1 small dent.
On the other hand, when I briefly owned a cheap netbook which was subjected to the same abuse my MBP's withstood for years besides small dent, the netbook couldn't withstand the same drops and I ended up with a dent in the plastic lid that permanently damaged the LCD screen.
We of course have no way of knowing what type of lamp the previous poster dropped on his MBP, as some lamps weigh 100 pounds and others only a few ounces, so without further information as to what type of lamp, we can only joke or speculate why it caused damage.
As for my iPad which I've owned for 2 weeks without a case, use a business card holder stand, and carry in a North Face surge backpack, it has no scratches/marks on the screen or back of the device and still looks brand new.
If your the kind of person who drops lamps on your iPad, throws your iPad onto tables, slides it across tables, or store it in a bag with your car keys when you are traveling, then yes it's going to scratch or dent.
However, if you take care of your iPad and handle it with care, then it's very durable and will not scratch or dent easily. The durability of the iPad all rests in the hands of its owner and how well they take care of the device.
The macbook aluminium is very prone to dents. I dropped my lamp on it and it created a very ugly dent. I'd say its relatively scratchproof, but not shockproof. Wrap your ipad up in something tough. I have a feeling that the apple case will not prevent damage if you drop the ipad with it.
I think the point is that if you dropped a lamp on any other plastic laptop it probably wouldn't have done any damage. But aluminum dents and you can't do anything to fix it. A plastic case would just absorb the impact and protect the laptop.
I have about 10 different electronics around me right now that if I dropped a lamp on it, nothing would happen. So no need to be sarcastic.