I have 3 account of different domain names, one for work and 2 for personal, they all actually using gmail's service. After I add all the 3 accounts, they all show up as "Gmail" in the Mail app, no way to know which one is which account until I click into it.

Is there a way I can rename them rather than "Gmail?

If I set them up as Other Mail, I will lose the option of Gtalk for that account (which I use one work, one personal, not at the same time though)