New Case

for a budget case,912 is my suggestions-
http://www.amazon.co.uk/Cooler-Master-HAF-912-Plus/dp/B...
for a little more,922 or 500r or phantom 410 are great cases-
http://www.amazon.co.uk/Cooler-Master-Tower-Transparent...
http://www.amazon.co.uk/Corsair-Carbide-microATX-Tower-...
http://www.amazon.co.uk/NZXT-Phantom-Midi-Tower-Chassis...
there are also some more expensive options but i don't think you need them.

Check the galleries in homebuild and overclocking, see which cases grab your attention, I vote for an In Win Dragon rider, but what is your intended spend on a case?
And Corsairs Tx850 would power that setup fine but try building your rig into This calculator to see what wattage Psu you will need
Moto

^thermaltake is definitely not the most reliable brand in terms of power supplies.you trust their power calculator?

I think you would save money f you bought all your components from scan.co.uk when you factor in all the different delivery charges.
As for a good case then i recommend either of these depending on twhat you can afford.


http://www.scan.co.uk/products/corsair-carbide-series-3...
http://www.scan.co.uk/products/corsair-carbide-series-4...

Argh .. hellfire stole my thunder ... All his pics are good imo , however , aestheticly speaking I'm only good with the 500r .As far as the Dragon rider goes I have to plead ignorance as far as first hand knowledge or even knowing someone who owns one but the reviews I read did say that that with the stock sidemount fan installed you couldnt get the 212 evo in ..... happy hunting

what's the deal with happy hunting?

As a rough guide to your needs yeah, its about the same as any online calculator will give, I always allow headroom ofc on top of what they 'recommend' but I wouldn't use their Psu's  
@Rufus, you know the Dragon rider, You've seen my rig hehe but yes, there is the sidefan issue with larger heatsinks, I'd remove the sidefan anyway
if I ever did an airbuild in one
Moto

Is that what that was ? 10 points from me . Hellfire are you picking on " happy hunting " ???? lol don't know where that came from .. and people with glass avatars shouldnt throw stones   happy trails

^  

I've decided to get everything from scan, so I picked out this case:
http://www.scan.co.uk/products/fractal-design-define-r3...
Any thoughts on this case, and whether it's a good choice or not, will everything fit, is the cooling good?

If it's not a good choice, is there anything from scan that's the same price, but better?

its a good choice and will suit your needs perfectly.

Fractals a great case :-)
Moto

agreed .. go for it