Deluge
After upgrading from 1.0.7 to RC2 (I skipped RC1) I have such a problem. Deluge starts fine, it downloads/uploads everything as it should be. But after that at some moment (couple of minutes after a start) it begins to use 100% of cpu time. 'top'-command says it is 'deluged' eats so much. Network interfaces loading decreases to zero. And Deluge just hangs up.
Upgrade RC2->RC3 didn't help me.
I use builds for Debian lenny from the 'downloads'-page.