An often-overlooked feature of 1Password 4 for Mac is Multiple Vaults:
Each vault can be assigned a custom icon, colour, and password. It even has its own sync settings, which means you can sync your primary vault with iCloud, for example, and a work/team vault with a shared Dropbox folder.
I’ve recently started a new job and use this function on my work Mac, it’s just great. Keeping my work-related passwords separate from my personal ones means I can keep everything compartmentalised, ensuring I don’t litter my own 1Password vault with server logins and intranet sites that I really don’t need outside of work.
It’s by no means completely fluid and is only applicable on 1Password for Mac, but it works very well indeed.