Darkage,
Consider getting an Adaptec 29160(n) SCSi160 card, I run one and its the bees knees.
Also for your SCSI drives, two 36gb MAxtor Atlas 10kIIIs would do you proud for OS and programs, and a western Digital caviar 2100Jb 120gb IDE drive for storage.
the 10k III go for about £150 each, the 29160 is about £270.
both of them are SCSI160

Watercooling...uhm. Just make sure its insured. Failing that, get a vapochill

Also consider a tyan Thunder if you want SCSI..since it comes with a DUAL CHANNEL SCSI160 controller inbuilt+AGP pro, 2 3com 100base net cards and some other server-type bells&whistles.
No DDR333 and not much OCing tho!