Nickel, black, dark bronze would probably all work. Are you looking to update the shape of the handles as well? If so, that depends on your door/trim style... you wouldn't want traditional hardware on a modern door, and vice versa. Post a pic of your doors/trim if you want input on shapes.

simstress This is my door

Brushed nickel levers, very simple lines.

Our floors and banister are the dark brown and our kitchen/dining floor is the oak wood look tile:

Here are the door knobs currently in the greenish ANTIQUE brass.

We had a lot more antique brass, but are transitioning the brass to the AGED brass look, like this in our kitchen/dining pedant (also have chrome in kitchen):

suzyq53 Thank you. Could you explain why brushed nickel?

I currently have aged brass, chrome, and stainless steel in the kitchen. Wouldn't a brushed nickel be introducing yet another metal? I also will be redoing bathrooms in the next year and would likely use a bronze, aged brass, or a black set of fixtures.

I feel like the door hardware doesn't need to be a highlighted design element and with white doors something clean and light sort of disappears and does not compete with other fixtures where you want to make a statement.