dont get me wrong... consoles are nice (i have a ps3 myself) but a pc is always more powerful.
while true that amd cpus normally tend to be less powerful, less power efficient and generate more heat... they are also much cheaper. the difference between an i5 and 8320 for example is $100+. the z87 motherboards are also a good $20-40 more in many cases with some being much more expensive than that.
something like the 8320 is just just under or equal to i5 in many cases and overclocked a bit will get into i5 performance levels which is perfectly fine for gaming. if you went with the 8350 for just a bit more with that 990x motherboard the chances of a good lucky cpu are better and you could end up with a pretty hefty overclocked chip which is quite a bit better than stock i5. even stock the 8350 is better than the i5 for most things
http://www.anandtech.com/bench/product/697?vs=837
amd cannot really compete with the i7 though. however you dont need an i7 and would be at the i5 level anyways so it doesnt really matter.
one thing i would do is probably bump up to a 7870ghz or 270x if you can stretch your budget just a little bit more. stretching up to a 8350 is optional but recommended. you'd be looking at about 525gbp with the 8350/7870ghz which isnt too bad. a better upgrade for the price would likely be to get the 8320 (and a cooler to o/c it) and upgrading your card to a 270x. it should come out to about the same price as the prior upgrade.