Here are some ideas for vintage painted built ins. Use Amy Howard One Step Paint from ACE Hardware

I recommend Annie Sloan chalk paint, approx $45 a quart and easy to use, one quart will do all of those cabinets with ease, Google chalk painted furniture and you will see most is done using her paints, very easy no sanding and easy to apply leaving no brush marks,I also recommend a color, she has many colors to choose from

I would look into adding a mirrored backsplash to go with your cabinets, it would go with the style and reflect light around the room

Also maybe adding glass shelving in the upper open glass doors would look cleaner than the white wood ones

You're very lucky - this cabinet is terrific. If you have a handy person in your family, add Shaker style trim and paint the cabinets a darker white. If you want to keep it a simple project, I'm with previous poster: paint it a green or blue; some darker color to coordinate with the rest of your kitchen. At the very least, change the knobs and repaint - a bin-pull style in dark bronze, black or nickel.