Spotlight is such crap.
Spotlight, Apple's answer to Google Desktop (or possibly Apple's answer to Longhorn's Vista's never-completed über file system), just doesn't work. It's garbage. It eats up my system's memory and CPU at random intervals. It chugs along super-slowly and can't even find anything most of the time.
Often, I will be looking for a file, and I can with my human eyes and hands find it faster than spotlight. Which is easy because a lot of times spotlight can find it like NEVER. Seriously.
Maybe it's just me; maybe because I have 30,000 files adding up to 115GB, Spotlight goes non-linear.
So don't run out and buy Tiger because you believed Jobs' demo of it. The reality distortion field still works.