Two Builds and would like your help, Have fun

I built my gaming rig 4 months ago and plan on selling my crapbook pro. The two builds are completely different in budget and in scale. 

The first build is fro my girlfriend, i would like to keep the budget around $600-$800 the uses well not be much. She does light gaming nothing serious liek BF3 but having a graphics card is something she wants. The CPU and GPU just have to be able to last a few years of moderate use, again nothing fancy, parts that can overclock well are nice and usually the smaller the better BUT if its cheaper to go with a mid tower that works as well. The catch is that their HAS TO BE A MONITOR 1080p. If the budget is $825 i will live with it and i look forward to seeing what you guys can come up, feel free to suggest anything. The second build is just something out of my knowledge.

I want to build a ROM box basically to hook up to my 55inch TV and treat it like an arcade system for when everyone comes over and has a few to many. I just want it to be able to play all Emulators and all ROMs. So having a big hardrive would be helpful as i would like to just make it a download whore for music, movies, and all other "legal" *cough forms or entertainment. SO i would like for it to be under $400 no monitor and the smaller you can get it the better, I will be cramming this thing under my TV and i already have a wifi stick. I might be wrong but maybe an APU might be the best. 

Ok well if you managed to read all of that thank you and hopeufllly you guys have some really good ideas. again if their is any questions or any parts you want to suggest go ahead and let it rip. Enjoy and have fun with it.

Honestly if she does light gaming 600 - 700 might be excessive. I'm too lazy to make a build but I think a system with an FX 4300 paired with a NVidia 660 (or even a 650ti) will be just fine.

As for the rom box, just get an A10 6700k without a dedicated graphics card. Cram it inside the small form factor case of your liking and you are good to go.

well that is an option, i have a few builds set out for each category but i just wanted to see some cool ideas, but i do appreciate you feedback and i agree mostly. The rom box would probably be ebst with a APU but maybe even a athion x2 or x3 and a 6670. All in good fun =) ty.

It isn't really much different performance wise, the APU compared to an athlon paired with 6670. The main advantage is that you use less watts (65w) and have a smaller overall build.

well that is good point as well. I was just looking for options and for everyone to have fun with it.