GDS vs Vista
I installed Google Desktop Search on Vista, but left the Vista search alive as well, so I'm indexing everything twice. I'm sure I'll shut that off at some point, but it's interesting in that it gives me the ability to search my system with both tools and compare the results.
One significant result is that Google Desktop Search is way faster than Vista's search.
A simple test: Search for a specification that I have in a PDF file in my Documents folder. GDS returned it seemingly instantly, while typing the same search query into the Start menu caused 10 seconds of disk grinding before giving me the same first result.