Resolution choosing - Dell 2407?

I'm considering the Dell 2407 as it seems to do pretty well in reviews.
But what concerns me is that the native res is so high at 1900 x 1200.

Now obviously to run a game in that resolution is going to take some hefty processing.
I'm planning to get a Core 2 - 6400 and an ATi X1900GT and I'm expecting to have to reduce the resolution to get decent frame rates.

Now my question is, can I reduce the resolution of a game whilst forcing the monitor to stick with it's native res. ie, display a 1680 x 1050 image in the screen without any nasty scaling going on, but having some empty black screen around the edge instead?
Or would I have to live with the scaling?

And this a graphics card thing rather than a screen question?

Mark