The clarity in the screen really makes a difference. Just shell out the extra bucks and get something that you'll keep a long time. Get the 3. The new iPad. Just buy a refurb from apple. The screen is night and day, and yea I've owned them all so this is first hand experience.
If there were a significant spec difference between the two, aside from the cameras and screen, I would agree with you, but there isn't really.
Power-wise, the iPad 2 will last as long as the iPad 3. So aside from resolution there won't be any apps that the 3 can handle that the iPad 2can't.
The smart money says get a used 2, find out if you like it, and if so get the 4. If you find yourself using the 2 enough to keep it, but not a huge amount then the 3 would have been wasted on you.