Best shoes and socks to wear with a navy blazer?

For a navy blazer paired with grey flannel pants, what are the best shoes to wear in terms of both color and style?

This is for a business environment, so it should be relatively formal, yet I would think Oxfords are too formal (?) for a blazer.

Also, what color/pattern socks would be best for this combination, or perhaps the same combination but with tan pants instead?

Thank you.