@MyPcProblem => Done the test, PSU dead, not working. Ordered new one, build it in, everything seems to work fine. Plugging PC in the wall directly now, no power-strips anymore, hope to avoid future problems.
@SouthJew =>
I got:
Core i5 4690k 3,5 Ghz
MSI GTX970
2x 4GB Corsair Vengeance DDR3 RAM
WD 1 TB Hard Drive
MSI Z97 Gaming 5 Mainboard
Thermaltake Chaser Mk-1 Case
Corsair CS850M PSU
I can run TW on a 1680x1050 monitor on (mostly) ultra settings with most post-processing on higher settings as well at 60FPS. TW3 is less demanding then I expected, which is a good thing I think. I take stable 60FPS over "better graphics" + 30 - 40 FPS any time.
Anyway,
if you have a budget I would recommend:
-> Intel Core i5 processor of the 4th or 3rd generation with 3,2Ghz or more
-> Nvidia Geforce GTX960 - if you want good cooling go with MSI, Gigabyte, Asus and the like, if those are too expensive go with other companies
-> Western Digital Hard Drive (Seriously, best HDDs I had so far) (Take the Blue or Black, not the Green (Green is more for office and similar applications, less for gaming and the like)
-> A standard Maiboard, don't need a "gaming" one. Just make sure it has the standards. 4xRAM slots for DDR3, Good audio, enough USB ports, enough Case fan connectors, maybe USB3.0, also look at the socket, current intel socket is 1150, look it has enough PCI-e slots for your onboard cards, and look it is ATX standard. Best companies are again MSI, Gigabyte, Asus, they got some budget boards as well so there should be enough choice
-> at least 6GB DDR3 RAM (take low level RAM if you want to save money, but look it's a good company, corsair, Kingston, Gskill) If you can, then take 8GB (best 2x4GB)
-> I'd also recommend a good CPU cooler, best company I know is BeQuiet, and they got some nice ones for a little price, Dark Rock series is nice
-> As for case, your choice, since the style is of course important, should though have enough space IMO, a backpannel for the cables if possible, and at least 2 fans, if not 3. If you want take a Big Tower, which is more expensive, if you need to budget go with a Midi-Tower but look for one which is described as "rather big" and "got enough room" in the reviews. Also dust filters never hurt.
-> As for the PSU, no idea man. I got recommended Enermax, but the one I bought was dead after 2 weeks, could be a coincidence though. Other companies I heard were good are Seasonic, Arctic Cooling and Corsair. Take one that has enough juice though. I took a 850W, but only because all 750W ones I liked were not available. So for you, if you have a budget PC, I'd say around 550 - 650W. Gives you some room to "extend" if you want to install and additional fan or HDD later on. But look that you get at least a Tier2 PSU, meaning it should have a 80+ Gold Efficiency seal or above (platinum or titanium), because that means more high quality components and a higher power output efficiency (bronze have 85% I think, gold have 92%, and so on). Means the more "efficient" your PSU is the less power it has to draw from the source to get the needed power into your PC. (at least that is how it has been explained to me).
Good luck.
Whatever you do though, don't over-save on the PSU (or any other part for that matter). It might seem like a good idea, but it came to bite me in the ass, even if all I had in the end was bad luck. Just don't over-save on one of the components only to compensate for the expensive other ones, is all I'm saying.
You can assemble it all yourself if you're clever enough not to hurt yourself with a screwdriver.
Prepare for SOME trying around though, and for a faulty hardware part in your final build (just saying it CAN happen, doesn't have to). Help is usually found fast and the faulty part can be identified after some research and testing, so no problem there. Just saying don't expect it to be all done without a sweat. If you are lucky enough though, and you keep cool if not everything works perfectly fine at first, in the end you'll get a pretty solid build for less money than you would have to pay if you would have bought the PC anywhere as complete package (and probably also longer lasting in the end). Also, once you did it you got some expertise in the field. Will become easier each time from that moment on.