Cooling systems no, there is a cheaper case that im buying very nice and well built with 2x 12cm fans if your that worried, but in my opinion no extra cooling will be required except one for the CPU but only if you intend to overclock it alot. A Sound card isnt NEEDED these days because nearly all modern Motherboards support 7.1 surround sound and for a daily basis good sound. But if your a heavy gamer and listen to alot of music a good sound card is a nice feature as it supports EAX sound for Games which gives good directional audio.
And about finding them parts that quickly for a good price well... i based it on my PC same parts roughly just higher versions, i have the X1950pro not XT and a Core 2 Duo E6300 not 6400.
By the way the E6300 and E6400 are Identical Chips except the 6400 has ahigher CPU multiplier giving higher Ghz, but if you no how to overclock then you could easily clock the E6300 to the same speed, without the need for extra cooling, so you could save 20 - 30 pounds there.
anyway here's the Sound Card i would reccomend if your a gamer.
If your prepared to spend £85 this sound card is phenomenal for gaming and still very very good for music and desktop
applications, however something of this price is noway neer need spending if you just want good surround sound audio
If you just want good gaming audio have this =
or if you want to spend much less but still good surround sound this =
Thanks and glad to help, anymore questions dont hesitate to ask.