Lamps and bulbs are disclosed generally comprising different combinations and arrangements of a light source, a reflective optical element, and a separate diffusing layer. This arrangement allows for the fabrication of lamps and bulbs that are efficient, reliable and cost effective and can provide an essentially omni-directional emission pattern, even with a light source comprised of an arrangement of LEDs. The lamps according to the present invention can also comprise thermal management features that provide for efficient dissipation of heat from the LEDs, which in turn allows the LEDs to operate at lower temperatures. The lamps can also comprise optical elements to help change the emission pattern from the generally directional pattern of the LEDs to a more omni-directional pattern.