Red Wing Standard Boom.
Manfrotto 087NWB 3-section crank stand with Wheel Set 104G (100mm, with brakes). Maximum height is 370 cm.
Weights: 3kg for wheels, 17lb for boom, 25lb for counterweight, 21.4kg for stand.
Total setup weight: 44kg/96lbs.
This allows me to place a payload of up to 15lbs 6 feet horizontally displaced from the stand's center column. With the 48-inch extension arm (as opposed to the default 18-inch extension arm) it extends the reach to approximately eight and a half feet from the stand.
One of the primary reasons that I have gone with this boom is that it is a parallelogram design. A parallelogram causes the center column to remain horizontal (or, at least, perpendicular to the stand) regardless of the height or angle of the boom itself. Once set, an attachment such as a monolight will remain at a constant angle even as one moves the boom up and down.
Something mildly amusing is that I took two days to realize that the Red Wing Boom's bottom portion (with 5/8" female) actually is a 1 1/8" male as well, which means that it does not require any adaptors to fit into the Type 14 socket on the Manfrotto 087 stand.
Thanks to Romy Young for the photo in use.