On every version of Windows I've ever used, the search indexing service steals precious background disk and CPU cycles, and almost always causes issues with the two main things I use my computer for: gaming and music production. I can't even count the number of times that the search indexing service spun up in the middle of a gaming session and made my system start to lag. Of course they say it runs as a low priority process, but heavy disk access is going to give you performance problems in CPU/GPU intensive games. Making music is no different - heavy disk access makes it that much more likely that my system will have audio dropouts or in some other way ruin my recording session.

I've disabled search indexing in every version of Windows. In Windows 7, it even makes the start menu almost non-functional because you have to make 3 clicks just to get to the Run dialog.