Personally, 3DS.

Whilst the NGP has impressive things, I've usually found the sum total enjoyment I get out of Nintendo exclusives outweighed that of Sony exclusives. But that's personal enjoyment.

Be getting both day 1!

Me want both!   Me getting both... eventually.

getting NGP cause i always go for higher spec hardcore games...

Gonna wait till they have more games.

This E3 is probably when I can make a prediction as to which one I may buy.

I've got the 3DS preordered, and will pick it up the day it releases in the US next month. I don't feel enough is known about the NGP right now, to say how interested in it I am. It defininitely won't be a luanch purchases. But if it comes in at a reasonable price and has some good games, I may get one in a few years when prices of older games have gone down.

Either NGP only or both.

3DS most probably soon after release (just like DS).
Although the known lineup doesn't impress me at all, I know I won't be able to resist. Different genres become tempting to me than on DS, e.g. I'm curious to see how 3D will work in football (NA) / football (rest of the world) / icehockey / golf and other sports games. Games that didn't interest me on DS or PSP.

NPG probably a few years after release (just like PSP), probably never.
If this will turn out to be just a portable version of PS3 I'm not interested. Need to know more.

I hope that someone develops or remakes a few western RPGs for one or both systems. This subgenre is still underrepresented on handhelds.

Hmmmmm

KotOR3 on handhelds

I would buy that

3DS pre-ordered.  Simple reason, the software line-up is already looking very impressive.