What about Port? I think it's a versatile color. Or dark grey.
I considered gray, but decided on dark blue verona. I'm getting it with both short and long removable straps. They allowed me to select the length for my short strap. Adds $$ but worth it for the use I'll get out of this bag. I dressed it up with gold hw. I think it will be dark enough to work with black and will match everything else I own very well. Should work for vacation too, as I wear lots of navy. If I like this interchangeable strap version, I could envision getting another in perhaps either a light color or bright color like the red pebbled.