Music fonts (designed for notation programs) usually compromise the spacing of a line, forcing you to use "exact" spacing. In addition, they are buried deep in the character set (with key combinations that only make sense when creating scores), and require extra dialogs such as Popchar or Special Characters.
Thanks to the Apple forums, I discovered most fonts do include the sharp, flat, and natural signs. But they too are not a key stroke away -- you have to use a character finding dialog. Likewise (and musicians are picky), the accidentals in most fonts (e.g., Times) look like an afterthought: cartoonish, and poorly spaced.
I'm now tickled with this solution: Use Ukelele to remap your keyboard so that Option-S, Option-D, and Option-F create the sharp, natural and flat characters. (I never use the characters that are normally mapped to these keys. And if I do need them, I can use the Special Characters palette to get them.)
A fellow Apple forum poster created a keymap for me (with instructions). It goes in Library/Keyboard Layouts. Choose it using the Input menu (after adding it in International Preferences).
The fonts that I think look "engraved" are Arial Unicode MS, Apple Symbols MS, and Lucinda Sans Unicode. I prefer Times, so I type everything in Times then change one accidental, create a character style in Pages, then find and replace that character style to swap them for Arial.

