Just bang in a 3.0 gHz Core 2 Duo , a Nvidia 8800GTS graphics card, a few gig of ram and a couple of 500 gig hard drives and you won't look back
I have all this in a 'tiny'
Silverstone SG01 case ...............
Not found that Diskkeeper does much for a 'normal' pc running NTFS but I guess something like a mail server , it may be very useful.