You've mentioned nothing about a GPU which is a very important part in PC gaming...?
-In my opinion intel is better despite a little more expensive. Intel i5 is perfect for gaming as long as you have a good GPU.
-8gb + Is a good amount for any PC really, especially gaming
-1TB HDD is a lot better than the one you said. You can pick up a good one for around £50/£60
-You might get away with a 500w PSU but its always best and more efficient to be about 100w more than you need just to be on the safe side
There isn't much point in paying as little as possible for a gaming PC as a starting one... Just wait a bit longer, save up, and make it better. Seems the best option in my opinion.