LED bulbs are a good choice because of the long lifespan, for example. The socket on the bulb is the quite common E27 socket, also referred to as an intermediate socket.
Conrad Electronic
Philips 8719514347168 LED (monochrome) EEC F (A - G) E-27 Pear shape 4.3 W = 40 W Warm white (Ø x L) 60 mm x 106 mm 1 pc(s)