Ditch that i5 660, get either an i3 530 or an i5 750.
If you overclock an i3 530 you get equal performance to the 660/650.
Also, nobody really needs the i5 660/650 unless you plan on using the integrated GPU.
You said she might want to upgrade to an i7 down the road?
Then get a P55 motherboard which was made for the i7 860/870.
Those CPUs with integrated GPUs weren't really made for P55 motherboards, so I'm a little confused at your build, also you don't have a motherboard selected?
Also, why stay with Intel?
AMD far surpasses Intel in price/performance.
Especially later this year when the Phenom II X6's release.
Newegg.ca - Rosewill Blackbone Black Steel / Plastic ATX Mid Tower Computer Case - Computer Cases
Also, I recommend that case over that ungodly overpriced three hundred.