Well the 660 should do a decent job on most games at 1080p, but 720p is always going to be faster because its' a lot less pixels. 1080p monitor opens up 1080p movies, youtube, etc as well and more screen real estate, so it's a toss up. Does she want her games to look awesome and not care if it's a lower resolution or may have to turn down a few things to do it at 1080p
Get a 1080p monitor if you can, you can always lower the resolution of the game if 1080p is too much for that card (which in most games it shouldn't be).
This is a cheap 1080p monitor, though it still may be out of your budget. http://www.newegg.com/Product/Product.aspx?Item=N82E168...
Just remember that the monitor will last longer than the rig. My BenqG2420HD was bought ~5yrs ago and has lasted me through three different builds. Getting a good one is important, because you'l have it for a while.
Nope, cant overclock on B75 (I think) and the processor is locked, so you cant overclock the chip even if you had a Z77 mobo. Turbo Boost should still be active though.
so will that b75 mobo turbo boost the i5 3470 up to 3.8?
also what do you think about my psu? should i have bought a better one? actually i can return it for a better one... any suggestions? (bare in mind that she'll oc the gpu)