Hmm, I'd say don't turn it off, but instead refine it. After your initial bedding in of the OS, its thrashing should be minimal. Its handy for instantly finding app folders spread through out normally hidden areas - App Data folders etc. I'd leave on myself, but make sure its configured to only search/index areas of interest.
You'd be far off better making sure that you have the likes of AHCI sata enabled than worrying about an indexed drive after its initial compiling.
All personal preference of course.
