I'd be happy with... the DualShock 3.
You are the controller.
The boomerang is comeing back! Oooh god how awesome what that be?
Just make the new xbox controller have a better d-pad.
The next controllers will be more comfortable versions of the NES game pad!
They'll have a microwave in the middle. You know, because all gamers are fat and stuff.
The 360 controller's layout is great but the sticks are complete shit, they're almost broken out of the box for me. MS needs to fix that and the d-pads. And I also think there's room for the black and white buttons to return on the left and right sides of the Y button. They could be small, not big, but I definitely think they could be used well.
As for the Dualshock? For my tastes, it just needs to be heavier and the triggers need to be curved upwards so that my finger doesn't slide off of them.
I think people have made their problems with the individual controllers pretty clear, fix the d-pad on 360 (I have the twistable one, and it's still not on par with other d-pads), improve L2 and R2 on the PS3 controller. I'd also really like them to get rid of that annoying battery pack on the 360, it makes holding the controller very uncomfortable, and I think the dualshock could stand to have its shape changed so that it's more comfortable. I'm still mad at everybody who bitched about the boomerang. Other then that I think the differences just come down to personal preference.