Solid state lamp or bulb structures are disclosed that can provide an essentially omnidirectional emission pattern from directional emitting light sources, such as forward emitting light sources. The present invention is also directed to lamp structures using active elements to assist in thermal management of the lamp structures and in some embodiments to reduce the convective thermal resistance around certain of the lamp elements to increase the natural heat convection away from the lamp. Some embodiments include integral fans or other active elements such as diaphragm-pump type active cooling elements, that move air over the surfaces of a heat sink, while other embodiments comprise internal fans or other active elements that can draw air internal to the lamp. The movement of the air over these surfaces can agitate otherwise stagnant air to decrease the convective thermal resistance and increasing the ability of the lamp to dissipate heat generated during operation.