If you go for a desktop, get one built to the spec you want instead of buying from PC World etc, As it will work out a lot cheaper for a better spec, and it wont be filled with loads of junk... For the price of the one in your link you could get one thats loads better.. I just had one built for £650 with a I7 processor, 16gb 1600mhz ram, 140gb ssd for O/S and software, 2TB slave drive for samples and such, and USB3..`Running Windows 7 64 bit.. Although i had windows 7 already so that wasn't in with the cost
before you splash out on albert0N i recommend grabbing some demo's or dare i say (illegitimate versions) of different programs, fruity, cubase etc. and see which one suits you best nothing wrong with it but well worth doing as you will always find different producers work better in different programs and you dont want so spend upfront to find out you want to use a different one right?
If you're comparing computers get the fastest frontside bus (FSB). FSB is outdated terminology though. Intel calls it ... something. Let's call it "Liquid Link". No! "Super Lube", wait wtf? Ummm, Mega Upl...fehhhhh, Supercardiod System Ligature. And AMD calls it HyperTransport.
FSB, GHz, RAM (meh, not that critical IMO - it's all fast these days)