It would be helpful if the the Default record option also showed which linode the IP selected is associated with, if you have multiple nodes and can't remember the IPs of all of them it's quite bothersome having to open the linodes page and find your IP that way when adding a new domain zone.

there is no requirement that your DNS domains be attached to a linode's IP. They're also not are they directly associated with any single linode.

A better idea would be to have a dropdown on the add a new record pages that would list linodes by name. If one is picked, populate the IP address field from that linode.

Yes, but the quick setup populates just that, a dropdown with all your IPs through linode, and this is where I have a hard time keeping track, since they're associated with nodes it should be a simple enough case to grab the name of the node they are attached to I would think?

Aha, yeah, I forgot about that quick setup. Putting the name of the linode with the IP would totally do it.