The first thing that should come to mind when you think of the holodeck is fantasy. A place where you can be whomever you want, wherever you want, whenever you want.
For Julian Bashir, this is playing his own version of James Bond. Unfortunately, because of lawyers and such, we only really got one good look at this, but "Our Man Bashir" is easily one of my favorite holodeck episodes. It combines a fun (if implausible, even for Trek) element of danger; the joy of watching a real spy like Garak complain about every inaccuracy; and the utter joy of watching our crew go through a story that isn't that out of place in the complete ludicrousness of the Brosnan Era of James Bond.
A lot of the success of the feel of the episode has to be credited to Jay Chattaway, who from the opening notes of this cue absolutely nailed the John Barry/James Bond musical aesthetic. From the pulsing "horns of danger" to a jazzy arrangement of Dennis McCarthy's DS9 Theme, it's the perfect complement to a perfect episode of Deep Space Nine.
Rather than choosing a single cue, I put together a quick suite of highlights from the episode.