Wife needed to move on from a 5 year old laptop which was well past its prime and after seeing me build my rig this past spring she opted to build her own as well. I helped her pick out the parts and left (most) of the building to her.
A few things I figure would come up in comments:
mATX mobo in a Mid tower - She got the mobo early on (bought all the parts over the course of 2 months) and originally wanted the Arc Mini but didn't see it go on sale for over a month (including BF/CM) but the Midi R2 did so she opted for that since its basically the same case with larger dimensions. Its a great case to build with and nearly silent. I'm pretty jealous of it after having worked with my NZXT Source 210 (which is still a nice budget case).
Keyboard is a hold over until she gets a nice mechanical one.
7970 for $0 - Yep, you read that correctly! My co-workers boyfriend works at a video game company and after the new line of cards came out they were going to be recycling the last gen cards so he gave both my wife and I each a 7970. I just picked the model it looks most like since the card is actually from AMD Radeon themselves.
She has yet to overclock as both she and I know pretty much nothing about it yet so we're going to view some tutorials before she dives into that.
Prices have sales/rebates/promos factored in.