Sigma
Sigma was founded in 1961 and it primarily know for providing 3rd party lenses and flashes for other camera companies. Sigma quality is said to vary considerably. They release a wide range of equipment from the cheapest to near-exotic.
In the Spider's experience Sigma represent the best and worst of the 3rd party producers.
They have a very interesting digital camera series made up of the DP1 and DP2.