Just for clarification, bitcoind is also a Bitcoin client, yes? When someone talks about bitcoind my association is hey that’s the official / reference command-line Bitcoin client. If one talks about Bitcoin-Qt I associate the official / reference GUI Bitcoin client with it. That’s no pro or con, I just want to understand what others read from a certain name.
To summarize: Bitcoin as the concept / protocol / technique bitcoind as command-line client using Bitcoin Bitcoin-Qt as GUI client using bitcoind