Problem solved! Apparently, updating the "Sharing X files" status is a CPU hog. As soon as it finished (it took a _long_ time... I've got ~2200 songs being shared) it went right back to using 5-8% instead of the 80-90 it was using before. Whew... thought I'd never be able to listen to my recently downloaded songs while I was downloading others.

Figured I'd post this in case someone else noticed this problem as well...

BTW... love LimeWire! I've re-upped my subscription every time it becomes available. Y'all are doing a great job. Keep up the great work.
---J