I th ink a nice cool gray like Benjamin Moore COVENTRY GRAY HC-169 would set off the cherry and black very nicely. A clean white that would work well for trim would be WHITE HERON OC-57. Your daughter sounds very daring and bold! Artwork with black frames and wide white mattes will be very nice with this. A collection of black and white photography or architectural prints would have beautiful impact. Floor lamps in shiny chrome or polished nickel with white drum shades would set this sectional off very nicely.