Bob Powell have some really good comments on where the power of WPF really is. He needs performance for constantly redrawing the grid. Something GDI isn't that fast at, and which steals all the power from doing the real work:

In order to liberate the processor we need to stop it from drawing the graphics. We still need the graphics so this implies that they need to be managed somewhere else. By the graphics card itself possibly.

Strangely WPF is here with a system that can make even the most bogged-down two dimensional application fly. With the power of graphics processors on even simple display cards today, the rendering of a grid can become a trivial matter, even when it’s data-bound to a constantly changing stream of data.

Forget spinning cubes, forget cards that bounce and shatter in a waterfall of broken shards, forget plasma fields with smiling babies and dogs catching Frisbees. Show the managers in your company the benefits of freeing up those expensive processors for doing real ork and leave the graphics where they belong, on the video card.

Some of the first things I noticed about WPF was the drawing performance of it. As everyone else I was of course right away thinking of fancy interfaces with spinning cubes and what not, and hadn't really given it much thought abot applying it in an "ordinary" application with some "ordinary" controls. But after reading Bob's post it really makes sense!