Spiders are definitely on many people's scary list, especially when they are as large as your hand. This is a golden orb weaver, most likely Nephila clavipes. The Nephila genus is rather interesting. Males tend to be much smaller than females, 1/10 the size of females, and live on the female's web eating their food. Males will mate with the female while she is busy, general while she is eating.
Of course, what the golden orb weavers are most famous for is their webs.
Their webs are a beautiful golden color, very large (1 meter or 3 feet in width) and very strong. Their webs are strong enough to catch a bird (not that they want to catch birds), and last for several years. There has been research on the properties of all spider silk, and some very innovative uses for the golden orb weaver's silk in particular. The silk of golden web spiders has been used to culture nerves cells, and may be useful as a 'nerve graft' as nerve cells adhere to it, it does not cause a major immune response, and is resistant to decay by bacterial or fungal agents .