I can see myself using an iPad for a myriad of reasons, and not one of them is games - although it could be used for that.
Actually the point is that pretty much it can't. It's a custom designed CPU loosely based on ARM, so you can't just buy a PC or even Mac game off the shelf and run it. And since Apple hates Flash (and everything that lets you bypass their monopoly attempt and run stuff that's not tied to their machine), you won't even be playing those games on it.
And with the integrated PowerVR graphics, you won't exactly be playing FPS on it anyway. It might be good for turn based games and adventures, once anyone gets around to make some for it.
But, again, given Apple's recent foam at the mouth against stuff that runs on more than one platform, the question might be if anyone actually wants to write an AAA title _only_ for the iPad. It's not like it will be the gamers' platform of choice or anything. I mean even the PC publishers now prefer to go cross-platform for major titles because the console market is that profitable. I doubt that any major title will actually be an iPad exclusive, as Steve Jobs seems to prefer his apps.
At any rate, that's speculation about the future. In the here and now buying an iPad for gaming makes as little sense as buying a pre-Intel Mac for running Windows.
You might however buy one to surf the web, or read an ebook or the like.
Really, as I was saying, gaming is not the common denominator there. Being new gizmos seems to be it.