Both drives are working fine.
The only thing slightly out of the ordinary was a little filesystem corruption, but fsck took care of that.
I have it running some memory tests right now.
When the new drives get here, I think I might take a full backup, and swap in the new drives, since they are rated for heavy use in a fileserver, and are larger and faster as well.
Plus, I had seen those timeout errors on drive 0, so it might just be a matter of time before something happens. I should download the WD drive test utilities, and see what condition the drives think they are in.