I just wanted to make sure no one forgets that wildcards can be used in your .ssh/config. This can be extremely helpful. For example say you have 100 nodes that have a simple nameing scheme of nodexxxx. You can add the following into your ssh config and pre-poplulate settings.
Host node* User staffuser IdentityFile ~/.ssh/staff_key
That would cause any ssh connection matching node* to use the user staffuser and .ssh/staff_key as the ssh key. By the same token you could do this.
Host *.locallan.domin.com User me
This could be useful if you have networks of machines that hook into different authentication systems. Nothing groundbreaking by any means but its useful so dont forget about it.