I'm probably going to get a blast here, but I don't really think that IDE raid is worth the hassles. If this were me, I would just hook up the 2 big drives as a master/slave setup on the primary ATA100 controller and hook up the DVD and burner the same way on the secondary (doesn't really matter which is master and which is slave). I would also recommend partitioning the drives, you really don't want a 100gb partition, trust me!
I dunno - I guess I'm just a believer in the KISS theory. (Keep It Simple, Stupid!)
Fans - if you don't have enough headers on the motherboard, just get fans with standard 4 wire "Molex" connectors on them and hook them directly to a power supply lead. Some high end video cards come with fans already on them, they are generally powered right off the card itself.