Deffo want a new GPU - the X50 line from Nvidia is pretty low-end from a gamers perspective. Your PSU looks like it could comfortably cope with whatever you're keen to get though.
That HDD - is that an 800GB HDD or 80? If 80, you might want to bump it up to 500GB, 80GB isn't a heap these days.
8GB of RAM should be fine for the moment, but make sure the motherboard has room to go to 16 - RAM requirements for games on PC were multiple times that of the same games on console, and in 3-4 years time I'd bet PC games need more than 8 at least. Checking the speed of the RAM (and the speed the motherboard can handle) is a good thing as well (same for speed of HDD - 7200rpm is better than 5400rpm). Faster RAM/HDD = faster loading, and better streaming.
When you get a GPU, pay attention to whether it's DDR3 or GDDR5 ram - while there was some speculation when everyone was talking console specs, my understanding is that it's fairly established wisdom that 1GB of GDDR5 is can better than 2GB of DDR3 in a GPU.
Overall price is pretty good, i5 is a good deal stronger than the CPU in the new consoles, and should be able to go the distance for a good while from a gaming perspective.
Anyways, that's some thoughts from someone who's fairly clueless on these things - wait for the PC guys to jump on and give you more informed comment

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On the by, a dualshock 4 makes a good gamepad on PC - my experience with Alan Wake has been pretty good.