New Gaming Rig $600 - $700 Budget Advice Requested

http://pcpartpicker.com/p/28Id7

Do you need a new copy of Windows 7? That's about $80. You'll be able to play Rome 2 definitely at high (As long as patches keep coming), you could also get an SSD, which will drastically improve your load up times in games and when booting up Windows 7. Any SSD is faster than a regular HDD, but some have higher failure rates than others. 64GB is enough for OS and a few applications. 128GB is enough for OS and a few games. 256GB is enough for OS and plenty of games. I'd recommend a 128GB SSD, I found one for $80 on Newegg, most go for about $0.70-$1.00 per GB.

Processors- Intel runs noticeably better on Total War games, or RTS games, that's because Intel processors are lightly threaded. While AMD is better for heavily threaded games, Crysis or Battlefield. The Clock rate is not always the best way of telling what is better in a processor, neither is the number of cores. 8 cores for gaming is way to many (unless you're playing Crysis, where that game can use all of those cores.), a dual-core may be too weak now considering that many games have multi-core support, that's why quad-core is considered optimal for your price range. Don't worry, if you want that SSD an i3 can play most games at high settings or higher. Be sure to get the right Socket Type too, such as LGA 1155 or LGA 1150.

RAM- 2 sticks of DDR3 @1600Mhz with C9 timings "9-9-9-27" is what you're looking for. You can get either 4GB or 8GB, I'd get 8GB just to be one the safe side for the future. More RAM however, is entire un-benficial, faster RAM only gives a little more performance. You'll also want it to be in Dual Channel (2 sticks). Avoid single, triple, and quad channel, those can cause compatibility issues. Intel recommends RAM running at 1.5V, AMD recommends RAM running at 1.65V.

Motherboard- Connects everything in your computer together. How many SATA connectors will you need, for your HDDs, SSDs, and optical drives? How many PCI ports will you need for graphic cards? Are you going to overclock? If so, get a Z77/Z87. Motherboards don't contribute to performance either.

Graphics Card- What brand and what model to get? All brands are reliable, the models is what you're going to want to look at. AMD or Nvidia? Both are fine. Do your research and look up benchmarks for the games you'll be playing.

AMD has just released a new line called the R-200 series, such R9 280X, or R9 290X. The R9 270 (no X) costs around $200 and it is comparable to the Radeon HD 7870, which is priced at around $130 currently on Newegg. The two GPUs are very close in performance, with 270 performing only marginally better, which is why you'll want to do your research and look at benchmarks.

For comparison:

R7 260X = Radeon HD 7790/GTX 650ti
R9 270 = Radeon HD 7870/GTX 660
R9 270X = Radeon HD 7950/GTX 660ti/GTX 760
(Only very rough estimates; AMD usually performs better at the low end while Nvidia usually performs better at the high end, but not always)

The sweet spot for price/performance is considered the 7870/gtx 660.

Power Supply- Powers your components. Why spend more money on one? Higher quality PSU's will deliver cleaner power to your components, higher power conversion efficiency (saving on your power bill), tighter voltage regulation and less power rippling. Cheap ones will produce more heat and noise and may not provide the rated wattage.

This is the PSU's efficiency rating. There are 6 levels:
no 80 PLUS certification - below 80% efficiency, stay away from these
80 PLUS - just reaches 80% efficiency, these are below average and should be avoided
80 PLUS Bronze - stays between 82% and 85% efficiency, these are average and recommended
80 PLUS Silver - stays between 85% and 88% efficiency, these are really great but (strangely) rare
80 PLUS Gold - stays between 87% and 90% efficiency, amazing enthusiast level
80 PLUS Platinum - stays between 89% and 92% efficiency, top of the line stuff; server quality

Modularity? Regular PSUs have the cables fixed into it, with a semi-modular or fully modular PSU you'll be able to take out the cable you don't need. Keep in mind you still have to tuck those cable away for good air flow. Also be sure to get one with a single 12V power rail.

Heat Sink- Disperses the air from your CPU across a much larger area. Intel's new Haswell line runs very hot, so be sure to get a decent heat sink if you go with Haswell. The Hyper 212 EVO is a great HSF for $30, but you don't need a HSF, usually only need one if you're overclocking, or if you just want a little peace of mind.

HDDs and SSDs- Your hard drive is for your general storage, ideally you want 1TB with 64MB cache running at 7200RPM. An SSD has no moving parts, and cannot be heard, but is very expensive. Be sure to read reviews for SSDs, as some have higher failure rates that others.

Case- Houses all of your components. Do you want nice aesthetics and LEDs? Good cooling? Nice cable management? A sturdy case? No loud fans? Think about where your preferences lie because you usually can't have it all. Be sure it's also large enough to house your GPU and can fit the rest of your components.