For those of you with experience or knowledge (er hem Blade) is it better to use Isopropyl alcohol or water or even distilled water for watercooling. Electrical conductivity is of no worry to me so that doesn't matter. I know alcohol has a very small density when compared to other liquids such as water, but does this matter for heat transfer? I will most likely be using something like WaterWetter in combination with the water choices. Please help! This is the first time I'm trying watercooling.

MSI K7T Turbo-R (sweet)
dead duron...750 soon?
256MB PC150 CL2
S3 Savage2000 64MB AGP4x
Buslink 12x/40x DVD
Sony 12x/8x/32x CDRW
300w PSU + 150w AT (450w)
CompUSA 17" 1024x768x32