Neutraface numbers, inspired by architect Richard Neutra, designed by House Industries, and available from here. For your home, your home away from home, or your lemonade stand. Image from minimalicious.

Numbers on homes on the the island of Salina in the Aeolian Islands.
via 30gms.

Nice looking stick-on numbers (and letters) are available too from the comfort of your computer. Go online, choose your font and layout, results shipped to you, ready to apply.