I must be in some pretty good leagues because I wouldn't say I've seen anything really high quality dropped.
In the RHRS roto-league (14-teams) I was surprised teams let Matt Read and Jakub Voracek go. I used waiver claims to nab both.
I'll say this... seeing Tim Thomas added in a one-year pool was by far the worst ADD I've seen this year. Hilarious. Team dropped him a few days later.