SSD Crucial, specifically the MX100. Crucial are partners with Micron, the fourth largest semiconductor company in the world. Micron has an excellent reputation as a DRAM and NAND manufacturer and they've partnered with the likes of Intel in the past. Intel is the more expensive here, but I've yet to have one fail. HDD I'll be honest here and I'm not in the know about Seagate. All my HDDs have been WD. The colours represent the tiers in quality (or NAS drives such as Reds). I usually go with WD Blacks, but WD Blues are great when on a budget. I found that WD Greens have a higher failure rate than Blues or Blacks, so I tend to avoid them.
AMD is cheaper for the power you get, Intel is more efficient with that power. If CAD is your plan, an i7 would be quite beneficial in the long run. This is due to Hyper-Threading i7s have over i5s, which can split it's cores to help processing power.
8GB is enough for gaming. Any work in CAD design, video rendering and the like will benefit from larger amounts or RAM. The more you get, the quicker the compile times. There is essentially no difference in RAM manufactures, modules either work or they don't. What you look out for is CAS Latency and speed. RAM in the 1600MHz range would have an average CAS of 9. The lower the CAS the better. The higher the speed, the higher the CAS. So a DIMM of 1600MHz CAS 9 is equivalent to 1866MHz CAS 10. On average the gains from faster RAM is negligible as the CAS also increases, effectively nulling quicker compile times.
For AMD there's really only one choice at the moment, and that's the AM3+ socket. For Intel there are 2, the LGA1150 and the 2011-3 sockets. LGA1150 are enthusiast boards that support the i5 and i7 you mentioned, where as the 2011 is the workstation board for high end workstations or servers. 2011 is considerably more expensive than 1150 boards since they support 8 modules of DDR4 memory and CPUs with more than 4 cores.
Titans are a waste of money, and you could buy two 970s with that kind of money. For gaming either the 960 or the 270X are fine. I'd suggest saving up and getting a 280X instead.
You don't really need 1000W, as the average gaming computer uses 300W-400W. Power supplies are the most efficient at 50% load so a 600W PSU is great. Only when overclocking, SLi or Crossfiring would you need a larger wattage PSU. Corsair CX power supplies are the lowest build quality PSUs. If you want Corsair get an HX or AX series, but they thend to be more expensive since they're really Seasonic re-brands. EVGA has some decent cheap PSUs lately, so between EVGA and CX, I'd go with the EVGA.