Well, when I got my MBP I was surprised, as I had seen people describe it many times as "silent" or "almost silent". And yes, there is a constant fan sort of noise even when the machine is just idle. There's no way it could be considered "almost silent". My iPhone is "almost silent".
It's all subjective - I work in audio too, so "silent" for me (and probably you) clearly isn't what a lot of people consider it to be, or mean.
It is, however, "silent" compared to my old PowerMac G4 mirrored-drive-doors, and my PowerMac G5! When the fans are at ~2000rpm that is - it makes a right racket when it's actually doing anything.
It's no problem though, most of the time.