|These will depend on your uses.|
For most general use a dual channel memory kit 8GB (2X4GB set) 1600MHz DDR3 would be best. For working with very large files, Photoshop, 3D AutoCad, and similar, go with larger like a 16GB (2X8GB set), and for gaming or where speed is more important than amount of memory, 8GB (2X4GB Set) 1866MHz DDR3 or faster.
For the graphics card, it also matters what you are doing.
For general good graphics, you may be fine with a GTX650, but for more graphics intensive work or gaming, you may need to go up to the GTX650 Ti, GTX650 Ti Boost, or GTX660 (possibly higher) depending on use and budget. There is no reason to avoid Radeon cards (though I have for a few years now) so look here for comparisons that are budget based:
You have to be a little bit crazy to keep you from going insane.