A lamp comprising a solid state light emitter, the lamp being an A lamp and providing a wall plug efficiency of at least 90 lumens per watt. Also, a lamp comprising a solid state light emitter and a power supply, the emitter being mounted on a heat dissipation element, the dissipation element being spaced from the power supply. Also, a lamp, comprising a solid state light emitter and a heat dissipation element that has a heat dissipation chamber, whereby an ambient medium can enter the chamber, pass through the chamber, and exit. Also, a lamp, comprising a light emissive housing at least one solid state lighting emitter and a first heat dissipation element. Also, a lamp comprising a heat sink comprising a heat dissipation chamber. Also, a lamp comprising first and second heat dissipation elements. Also, a lamp comprising means for creating flow of ambient fluid.