I don't know anymore. There are so many definitions of goth nowdays, especially music. For example:
There's classic goth music, like the Sisters Of Mercy (including the greatest 80's pop song ever made, This Corrosion) and Bauhaus. There's Victorian-style goth, but that's rare. The only good example I can think of is Rasputina. (Their song "Transylvanian Concubine" was on a Buffy soundtrack.) There's electrogoth, like Switchblade Symphony and Faith and The Muse.
After this, things get fuzzy.
Symphonic metal, like Within Temptation and Lacuna Coil, is sometimes considered gothic metal. Industrial music, like Nine Inch Nails, occcasionally mixes with gothic music. Electrogoth and electropop sometimes overlap, an example being Ladytron and Depeche Mode. There's pagan rock, like Inkubus Sukkubus, but the only reason that has a gothic following is because many goths follow a Pagan or Wiccan path.
In conclusion, no one knows what goth is anymore, because it's forked so many times. However, it is agreeded upon that Marilyn Manson is not goth.
"What is gothic music?"
"I...just don't know anymore."