You cannot really get into this discussion without getting into a lot of how the scenes work themselves and the ever so popular question of "what is goth?"
Well just about any group has the "popular kids" and the "outcasts" even with in the group. You can subcategorize anything pretty much. This could be done by the type of music listened to, type of dress, people they associate with, or all three.
http://www.odk.com/wilson/goth/150.html most of these are made up, some are pretty accurate though.
http://www.sfgoth.com/primer/types.html shorter list and quite possibly more accurate.
I myself am a gothabilly or a "gothick" (I like to think I came up
with that one) or cowgoth. However I don't limit myself to this one
subsection of the subculture either. Two of my favorite bands are Ghoultown and 16 Horsepower. Think Victorian/Edwardian era goth in the old west (I like to throw steampunk elements in as well.
Then again there are those that don't label themselves as such. They don't want to be typecast as goth. Which is ok too I guess even though they still are goth (denialgoth lol).
As far as the music goes you've got Deathrock, Folk/traditional goth, Industrial, EBM/Synthpop, and now Emo. Examples of each include...
Deathrock: Bella Morte, 45 Grave, The 69 eyes, Beseech, and The Misfits
Folk/traditional (some post punk fits here too): Bauhaus, Joy Division, Tom Waits, Nick Cave and the Bad Seeds, Clan of Xymox, The Sisters of Mercy, Siouxsie and the Banshees (a lot of this stuff blends in with the afore mentioned genre too).
Industrial: Ministry, KMFDM, DAF, SPK, Skinny Puppy, Nitzer Ebb, Unit 187, Static X, Fear Factory, Front 242, and Nine Inch Nails, :wumpscut:, and Blue Eyed Christ
EBM: VNV Nation, Covenant, And One, Apotygma Berzerk... Easiest way to explain it is tune your radio or television to a station that plays dance music. Now make the lyrics and melodies dark. This was created so the goth kids at the clubs would have something to dance to.
It should be noted that EBM of the late 80's and early 90's and EBM of today have NOTHING in common. Skinny Puppy, Front 242 and Nitzer Ebb were once considered EBM.
Oh yeah then you have Emo which is today's bastard child of goth. My Chemical Romance, Hinder, The Cure, Morrissey (pretty much any whiny band from Manchester).
It should also be noted that I do love the cure, but they're still Emo.
The major difference I've found between the two is that Emo kids hate themselves (and their girl they have a crush on for not loving them back). Goth kids hate everyone else. Each have an equal amount of angst (which is pretty much anger without direction) and have a common enemy (the preps/jocks/whatever you want to call the normal people). I still battle them because even at the ripe old age of 26 I still get picked on from time to time by people who haven't yet left the high school mentality behind and probably never will.
Then there is the woman factor. We can't leave this out at all because it's also very important. Girl A dislikes girl B because of "drama" so the friends of these two popular girls split in two creating two groups. In my town they apparently split into different companies that specialize in fetish shows and modeling (I think we're up to nine (9) just off the top of my head). Sure men have drama too, but they usually settle it in a fist fight that lasts about 5-10 minutes. Women will drag it out for months/years before any resolution is solved, which is sometimes never.
This concludes part one of my ramblings. If anyone thinks I've forgotten anything, gotten anything wrong, gotten it all wrong, or would like to congratulate me on my amazing insight into the inner workings of "the scene" please, by all means post a reply.