Spotlight Tips

There are some really good tips on using Spotlight (on a mac) in TidBITS Spotlight Strikes Back: In Leopard, It Works Great. I came across it because I was trying to figure out why Adium chat transcripts weren't showing up in spotlight results. Setting System Files to be included solved that. Now if only I could find a way to make the setting permanent or better yet have a particular way of invoking Spotlight to have it set (like an extra modifier key).