I agree with Dusty. The 3D does add a nice touch to the games, but does not change gameplay. (OoT3d looks amazing with 3D visuals, fyi)
Honestly, I would wait to get one until after Nintendo's conference next week...i'm waiting to see if they are coming out with a redesigned model, or just adding the circle pad peripheral for games. And if they are adding a peripheral, is it just for Monster Hunter 3G or are we expected to buy it for use in multiple games....If they come out with a remodel, I will be upset...I'll be upset if the slider peripheral is used for more than Monster Hunter as well.
I don't really want to pay for Nintendo's design mistakes. (Which is what this would be)
I think the 3DS is an amazing machine anyways, and doesn't really need a second slider pad, but...w/e.