WordPress@Domainname email – how to change?

I have a multisite install running a mess of plugins, and it seems that they here and there pick and choose how to send emails.

Example,

Username and PW

New Site Reg Alerts

Pro Sites Activation

Please Moderate Requests

Pro Sites Subscriptions and Cancellations

I have checked Network Settings and poked around in individual settings to no avail.

Any ideas?