Well I'm no expert and I'm sure people will bash me for my answers, but here's what Wikipedia thinks and I tend to agree:

EMO:
The term "emo" is sometimes stereotyped with tight jeans on males and females alike, long fringe (bangs) brushed to one side of the face or over one or both eyes, dyed black, straight hair, tight t-shirts (sometimes with short-sleves) which often bear the names of rock bands (or other designed shirts), studded belts, belt buckles, canvas sneakers or skate shoes or other black shoes (often old and beaten up) and thick, black horn-rimmed glasses.

Emo fashion has changed with time. Early trends included straight, unparted hair, tightly fitting sweaters, button-down shirts, and work jackets. This fashion has at times been characterized as a fad.

Another example of hair characteristic of emoIn recent years the popular media has associated emo with a stereotype that includes being emotional, sensitive, shy, introverted, or angsty. It is also associated with depression, self-injury, and suicide.

GOTH:
Goth fashion is stereotyped as a dark, sometimes morbid, eroticized fashion and style of dress. Typical gothic fashion includes dyed black hair, dark eyeliner, black fingernails, black period-styled clothing; goths may or may not have piercings. Styles are often borrowed from the Elizabethan, Victorian or medieval period and often express Catholic or other religious imagery such as crucifixes or ankhs. The extent to which goths hold to this style varies amongst individuals as well as geographical locality, though virtually all Goths wear some of these elements.

Goth fashion is often confused with heavy metal fashion outsiders often mistake fans of heavy metal for goth, particularily those who wear black trenchcoats or wear "corpse paint" (a term associated with the black metal music scene).

HEAVY METAL FASHION:
The clothing associated with heavy metal has its roots in the biker, rocker, and leather subcultures. Heavy metal fashion includes elements such as leather jackets; hi-top basketball shoes (more common with old school thrash metallers); motorcycle boots (harness and engineer boots), work boots or combat boots; blue or black jeans, flannel shirts or vests, and denim jackets or kutte vests, often adorned with badges, pins and patches.

So, here's some pics of emos/goths/metalheads. You can decide which on you are:

EMO:
1. http://www.fashionshanty.com/images/emo/girls-emo-haircut.jpg
2. http://img38.picoodle.com/img/img38/9/7/17/f_EmoLPGirlbym_0ee5861.jpg

GOTH:
1. http://www.gothik.ws/images/suicide%20girls%20gothic%20girl%2009%20-%20beautifull%20goth.jpg
2. http://donnkinney.easystorecreator.net/images/images_23048/GalleryPhotos/sitweb.jpg

METAHEADS/HEADBANGERS:
1. http://www.flickr.com/photos/jurek_durczak/176502994/
2. http://www.agoracosmopolitan.com/home/images/lifestyles/heavy_metal_fashion1.jpg

Keep in mind that these are all your average stereotypes. Personally, I listen to a lot of heavy metal and goth rock (and tons of other subgenres - symphonic metal, neo-classical darkwave, dark ambient, etc), but I wear Hollister, and don't wear makeup at all. Guess I'm kind of a mix of stuff *shrug* Personally I don't like emo people, unless they're the funny kind. You know, the ones with a lot of jokes and bizarre humor