Ok, for one, buy good drives, this will really help big time. If you want to stop them from failing due to mechanical error, dont shut your computer down, spinning a cold drive up all the time causes more damage then any other time, just like starting your car, the most damage happens within the first 2 mins.

To keep your drives running fast, have 2. Have one for windows and programs, and the other for storage. This will keep your general system speed a lot faster. Keep your file sytem neat. Dont fill your drives, leave at least 10% - 15% free. Run a decent defragmenting program often, i reccomend Executive Softwares Diskeeper - You can also set this up to run itself at a certain time every day. Most importantly, back up, if you don't then its your own fault for loosing stuff, and make sure you have the lastest malware and virus protection, dont go trawling crack sites, this is the best way to corrupt your filetable. Oh, and if you smoke, dont do it round your computer.