i do synch to visuals when i have got them to work to!!! but if i am trying to write a piece that might hopefully get picked up by a production company for an ad or ident, then the recomendations seem to be go for a hard ending, but leave the editor the option of a fade. (that's the feedback i have had from these companies...those that bother to reply anyway!)

i did one film when i only had a very rough draft off the editor...so i supplied a very ambient background piece, and several stings and cues all in the same key...and to his credit the guy did a great job layering it all up.