Need some advice on chosen parts for my new build

I agree with ignatzatsonic on the motherboard. It is a waste of money to buy a K CPU and an H77 motherboard. If you want a K CPU get a Z68 GEN 3 board or a Z77. The 3570K is a stronger CPU than the 2500K, but if you want to overclock it, you will need a better CPU cooler, they run very hot during stress testing. During normal useage they run about the same temps though. As far as cases, Coolermaster HAF cases are nice in that they use large fans that are very quiet and move a lot of air, Corsair makes some good cases but if you want to 'style' with your case, look at the Thermaltake Level 10, if you want to spend that much money. It is true that cases are a matter of taste, but you can find some nice cases that offer both good performance and good looks too, no matter what your taste is.

Case, case, case. Their are bunches and bunches to choose from. Some very good brands have been mentioned. Once you get past how pretty it is I recommend thinking functionality.
1. Does the case have very good cooling or better.
2. Does the case have the ability to improve the air flow by adding fans if you so choose to do so.
3. Does the case have access to the back of the motherboard so you can remove the cpu cooler if needed.
4. Does the case have a designed in method for proper neat cable management.
5. Is the case large enough to make it easier to work inside and add things later if you care to.
Note: Some Branded cases that are called full size are actually smaller than other Branded mid size case. Look at the measurements. Also conceder the weight. Normal the heaver case made out of the same materials have more material and are built stronger. Aluminum cases compared against other aluminum case for example.
It will take a little homework on your part but you computer will thank you for your efforts.

So far i'm sticking with the NZXT Phantom. I love it's unique look, but thanks for the guidelines.

I now have a new dilemma. Buy a gaming pc or build one myself. I can buy either but built rigs cost cheaper if i was to buy each part separately!

Tbh if it's going to save me money then i'd rather buy a ready-made system of my own choice, so I can get more out of my money. I'll only be spending roughly £800 nothing majorly more than that

Hmmm true true. I just want the most out of my money parents are helping me buy the pc anyway, giving me around £350 so tbh I don't mind it being around £800 either way.

I'd find it more fun in a way if i build a pc because it's sort of turning into a hobby for me, then i'd start overclocking and maybe case modding too. I just want to excplore the possibilities of computers! Plus my parents think i'm so cool haha

You also get to choose the quality and features of your own build. Most ready made companies put whatever parts the can get the cheapest in the machine. After all, like this discussion, they are competing on price, not quality and features. And if you buy from places like Dell, HP or Gateway, forget overclocking. The BIOS is locked usually.

Yeah i'm just gonna buy my own parts now. It's more loving then, like it's my own son rather than adopting a random one.