It's been a couple of years since I last tried beagle, the desktop indexer, so a couple of days ago I installed it again. Installation was a breeze as usual, I got it straight from the Debian repositories using synaptic package manager. It doesn't seem to impact system performance at all - it must do but I really have not noticed it, which was the reason why I uninstalled it last time and is all the more impressive as my machine is pretty low powered.
I especially like the iceweasel (aka Firefox) plugin that I installed from the Debian repository. With this browser plugin every page I browse is indexed - very useful. I also installed beagle at work and it has proved itself to be very useful for finding things in my copy of subversion repository. So far I've found Beagle very useful.
Just a little note about my low powered computer: It's an Acer Aspire M1610, 1GB RAM, 1.6Ghz single core Celeron. 3D acceleration works, albeit slowly and uses a lot of cpu when the 3d transitions kick in. It was very cheap. However this is the quietest desktop computer I have ever owned. It sits in our bedroom and we literally cannot hear it at night as I leave it on all the time. For this reason, and this reason alone, I love this PC - oh, and the screen is okay too.