A few hundred people stopping the data being collected would do nothing... if everyone did that, then it would be interesting to see the effect, and frustrating to get the right results.
A little healthy distrust of large companies is no bad thing, but I think it's also sensible to keep it in perspective, and to understand why they operate the way they do, because then you're making a decision that is at least based on facts rather than the fiction of many conspiracy theories that do the rounds.
As for setting up the music PC, I use an SSD for my main data - it makes sample based synths that much smoother to run. I have recently started slicing drives into many partitions, and keep each project on its own partition. I start a new project with a quick format of that partition - it's just much faster than defrag etc. and finished projects get archived into a folder on a large backup drive.
Working that way has enabled me to do far more with an old WinXP machine than I ever achieved on the same machine before. I can physically use far more tracks, more complex arrangements in The Grand and EastWest Symphonic Gold... it all just runs smoother than it did, so I'd like to think I've got it right.
As drives have improved performance and processors become far quicker, I think the gains to be had from particular arrangements of system data and recording data are much more marginal on modern systems. Just put an SSD in there for data and watch it go like a rocket - it puts all the other system wrangling to eek another few percent performance into perspective.