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
LightMe LM85251 LED (monochrome) EEC G (A - G) E-27 Teardrop shape 1 W Blue (Ø x L) 45 mm x 69 mm 1 pc(s)