If you're just going to be gaming and doing normal tasks, there's no point in getting 16GB of RAM. A 2x4GB kit will be more than enough for anything out there now and in the next year or two, and you can always pick up a second later. It's only going to really be worth the investment now if you're doing more specialized work like video editing or software development on the machine. If you don't, you'll be better off saving the difference or putting it towards a better video card.

Games built for 64 bit are only just starting to appear now, and so long as they still support 32 bit you can expect the benefits (and memory needs) to be more limited since they'll be made to work best within that limit. I haven't heard about any others that will be 64 bit only at this point other than GC3, and that's still quite a ways out from release.

And thanks to that Hynix factory fire, prices for computer memory will be high for a while, whether they use Hynix chips or not, strangely enough.

You forget the SSD disk! It's really important, you have to install windows on the SSD and then your computer will start up so much faster with it. Use a 256 GB sized one (because such a big one is faster than the smaller ones).

Also, buy a big cooler with a big fan, to reduce noise (it looks like your system will need a lot of cooling). If you use the (small and cheap) stock cooler, and your system is running at full speed, then your computer will probably sound like a small vacuum cleaner. You will need a big computer casing of course, otherwise the cooler won't fit.

You should turn it off when you don't need it, a computer like that consumes a lot of power (even if idle, could be as much as 200W doing nothing at all). That way, you can save some money on your electricity bill.

Your graphics card, about 110W:

http://www.bit-tech.net/hardware/2013/07/04/msi-geforce-gtx-760-twin-frozr-oc-2gb-revie/8

Your CPU, about 90W:

http://www.tomshardware.com/reviews/fx-8350-vishera-review,3328-16.html