Well, well, well, haven't we all had that problem?
I'm currently unsure whether I want to stay absolute budget - NSK4480 - or throw out an additional 70 quid for a p182 with an Earthwatts380. I rather save money, since the build is going to be a value for money rig - E2160 (and after market cooler), HD3870, 2GB PC6400, 320GB single platter HDD, Abit Dark raider/MSI Neo2, Samsung S203. So quite the minimum to have nice performance.
I cannot find pictures of the NSK4400 interior and apparently there's only one 80mm fan-mount in the front. Now, how difficult is it to slightly modify the case and install a 120mm fan instead? I have reasonable DIY experience, powerdrill and everything at hand.