Hi Tony

As above building own PC doesn't involve any kind of magic,just have good tools and most of the cases are now tool-less which will helps,really its easy and usual problems can be solved in matter of seconds or minutes 

I've been building the PC for friends and for me for few years and I've never have any kind of problem 

Usually I'm buying all parts from several suppliers,some suppliers can give some kind of discount,but most of the biggest players on market as Scan,Aria,Overclockers doesn't offer any kind of discount,if I would buy all parts from one supplier then I can end with much higher price(in my case when I've build for friend Hackintosh with i7 he would pay around £300 more than from several suppliers,because this supplier didn't have GPU,RAM etc which my friend wanted )

In UK you have 1 year or 2 year warranty which is much better than in US,where you need to RMA through the maker not the company/supplier from which you are bought the item

64bit is must there,I prefer W7 64 bit version,W8 is bit of hit of miss,I don't like this,I'm using now for few years W7 which is great,I've only once installed W8.1,but after few hours and some programs didn't wanted to start with mew W8 or W8.1,due this I reverted to W7 which is working in any app which I'm using,although looking forward to W10 which I will be installing on spare PC and we will see how good is Technical preview 

Water cooling you shouldn't need,although you can buy AIO(All In One) Water cooler kits something like is Corsair,NZXT etc which are something between,those systems are closed loop systems which are OK,proper Water cooling kits they can cost you crazy money and usually depends on the CPU and overclocking they're worth to consider

What I can't recommend is using OE CPU coolers/heatsinks those are rubbish in one word,they're don't like the overclocking or are very noisy,due this if you are don't like or don't want go with Water cooling I can recommend Be Quit! Dark rock 3 or Noctua NH-D15 which are best CPU coolers on the market and they're very quit and have awesome performance when you are overclocking PC,my PC is overclocked at 4.4GHz still on air and is very quiet on full and I've never seen any higher temps than 70C

Good case something is Lian-Li or Coolermaster HAF-X which I'm mostly using on my builds with good fans and you have nice PC,cooling on those cases is great and quiet,although I upgraded few fans to Noctua fans,but usually stock fans on those cases is very good 

Here is my spec which can cost you less,which is older spec,but still perform great in any 3D SW

Motherboard: Asus P6T SE

CPU: i7-920 4.4GHz with Thermalright HR-02 Rev.A(BW)

RAM: 20GB DDR3 1600mhz

HDD: 256GB SSD Samsung with 2X 3TB HDD Toshiba,2X1TB WD Blue

GPU: GTX560Ti

PSU: PC Power & Cooling Silencer Mk II 750W

Case: CoolerMaster HAF-X

This PC should cost you lot less than when I've build this PC few years back,but still perform very good in any app

Hope this help

Thanks,Jura