Sorry for butting in...

There's also the junk filter. Some people like it, some hate it but it's worth a try. It takes some time for the filter to be trained.
Junk Filter

And if you're using a version of LW 4.13 or later, there's Aaron's hostiles list...that should help reduce some of the crap! Read more about it here.
The TechNutopia Fullsize Hostiles List for BearShare and LimeWire