Maybe I'm the last person on the planet to know about this, but on a recommendation from macosxhints.com, I went into Finder Preferences and unchecked every language, even English, under "Languages for searching file contents." All of a sudden the Finder's performance sucks much, much less. (I'm using a 500mhz iBook with only 320 MB of RAM, not one of them dang hot-rods like you kids have.) I think I've asked the Finder to search within a range of files perhaps twice since adopting OS X; I'm much more liable to use grep. So this is a feature-for-performance trade-off I'm happy to make.