Well, the single thought I had about this was not mentioned. I will be doing it on a machine I am building in the new year, based around an Intel i7 960. That is to use an SSD to hold the OS. No aps, just OS and drivers. This will give a boost of around 100% I am told (using Win 7 64 bit).
There is no unused hardware, but moving unwanted fonts to another directory is well worth while also.