I have 3 cats, all Abyssinians, water cats. They used to be really interested in running water (especially the shower), but we bought them one of those drinking fountains and I think they got over the idea of staring at moving water.
When I got the 3rd one as a kitten, I wrapped my entire tank and stand with saran wrap to make sure he couldn't climb into the sump.
Also, my cats like to sit on all heat sources (cable boxes, stereos, external hard drives, halogen lights!), that is something to think about cat proofing if your cats are like mine.