I use to be in to this and have spent many a hour on the overclocking forums and also a few quid in the shop
never modded my case but i remember the time i brought a case from them called the tornado or something and it had 6 fans in it, 2 on top 2 on the side over the cpu 1 front and 1 back, god it made suck a racket i had to change all the fans over for quieter ones with less db output.
I have done the celeron chips with over clocked bus and voltage
Now i am just running a shuttle system with a p4 all standed which suites me