How can I make the Firefox Password Manager more intelligent?

LastPass FTW. (And Chrome.)

"i wouldn't use any bowser password manager, as they are potentially unsafe.

have a look at KeePass:

this feature might be of particular interest to you:

KeePass features a global auto-type
hot key. When KeePass is running in
the background (with opened database)
and you press the hot key, it looks up
the correct entry and executes its
auto-type sequence.

KeePass is open source, cross-platform freeware."