You will need to choose between Intel and AMD.. I have had an AMD rig for the past while now, going from an FX-4170 to an 8350 (4 vs 8 core) was a huge jump and the SSD definitely helps. I have a GTX 760 and I can run new games on high without much issue. For me the AMD works well, even though ideally i would like a high end intel chip, they are just cost prohibitive. I also run DAW and video editing software regularly with no hiccups. Lots of people go with AMD for there power vs cost ratio.
In the current CPU landscape, intel is ahead of the game in terms of chip tech, as AMD is still lagging behind with their Piledriver based desktop. The next AMD architecture is called Zen and is slated for release in 2016 at some time, which will support DDR4 and compete with the current lineup of Intel CPUs. The good news is all these new chipsets will drop the price on the prior gen stuff.
If you can afford it, spend the money and get a nice mid to high range intel CPU (check out
this list).
The majority of your budget should go to the video card, as that is one of the larger bottlenecks for current gen gaming. CPUs have come a long way and you don't need as much as you think to have a great setup.
If you have a PC already and have a HD to salvage from it, I would definitely try and get a decent sized SSD to boot from windows and keep some essential programs on, as it is truly incomparable to any normal HD experience
For RAM, I would stick with a 4GB x 2 (8GB total) setup for now as there isn't really reason to go higher than that unless you are a super power user with the media editing and what not. Perfectly fine for gaming
Corsair makes some nice cases with great cable management features, and I plan to upgrade this year.
good sites if you didn't know already are newegg.com and pcpartpicker.com