Yes do confirm everything.
If you want those photos of the case lemme know and I'll upload them.
If you could have another 100 quid I'd upgrade the CPU to an i5 2500K or an i5 3570K, and then buy an aftermarket cooler too and overclock it to over 4.0GHz. Got my 2500K at 4.3GHz with the Arctic Cooling Freezer 13. Awesome cooler, cost me £20 from Novatech.
Both the 2500K and 3570K will work with that board, the 3570K is the newer part.
A boot drive is a hard drive which you install your OS onto, you've already got one of those (the 500GB drive you were looking at). You don't need a cache card.
Yeah, I am only 14 years old.
No jokes, I am. Didn't realise you were 14 too, Hyper-Threaded. 
If you could have another 100 quid I'd upgrade the CPU to an i5 2500K or an i5 3570K, and then buy an aftermarket cooler too and overclock it to over 4.0GHz. Got my 2500K at 4.3GHz with the Arctic Cooling Freezer 13. Awesome cooler, cost me £20 from Novatech.
A boot drive is a hard drive which you install your OS onto, you've already got one of those (the 500GB drive you were looking at). You don't need a cache card.
Yeah, I am only 14 years old.