My order of preference would be the price order of the ones you list, the 40D has the best sensor and all of them have decent build/body.
A consideration though is that the Canon 50mm f/1.8 prime isn't a patch on the Nikon one in build quality, I've heard of quite a few just falling apart, never heard of that happening with the Nikon version. The Canon is cheaper though...
She's already bought a 30D.I'd go for the 40d, had a 30d a long time ago but will be pretty dated now. the 40d for not much more offers much better performance
I have just spotted it, only quickly glance through the thread before postingShe's already bought a 30D.
Unless the OP has already purchased a 30D.....Fuji S5 Pro are in your price range now, absolute bargains.