...and now I'm back to really snappy speed today.
I complained on Twitter about the speed of our GoDaddy account, and ended up getting a lot of public feedback telling us to move to another provider. GoDaddy themselves chimed in (on Twitter) and said they'd look into our trouble ticket. Now today, our website feels very fast from here.
We'll keep a close eye on things at this end...if the slowness returns, we might be better off jumping over to another provider.