House

House is perhaps the earliest form of modern electronic music. It finds its roots in the music of pioneers of the disco sound (Giorgio Morodor, etc) and in the Chicago gay clubs of the early 80's. House is distinguished by its 4/4 beat and (usually) hi-hat hits between beats. Excellent modern house producers include Next Evidence, Basement Jaxx, Kings of Tomorrow, and ATFC.

Trance

Trance is very similar to House in many respects, and some tracks are difficult to distinguish as one style or the other. Trance typicallay displays a 4/4 beat pattern, but usually with less focus on hi-hats on up beats. The genre finds its roots in the more melodious Techno tracks produced in England and Germany in the early 90's. Excellent trance producers include Paul Van Dyk, BT, Max Graham, and Man With No Name.

Techno

Perhaps the earliest purely American style of electronic music, Techno can be said to be the product of a trio of (at the time) boys from Detroit, MI, now known as the Belville Three: Juan Atkins, Derrick May, and Kevin Sauderson. Techno usually has a 4/4 beat with less emphasis on melody and more on complex layering of drum patterns and mechanical samples. Modern Techno producers include Plastikman (Richie Hawtin), Frankie Bones, and Heather Heart.

Drum & Bass

Drum & Bass music is often thought to be the British interpretation of Hip-Hop, and is one of the youngest distinct genres of electronic music. Drum & Bass' is often composed sped-up breakbeats from hip-hop-style tunes, sometimes with reggae and dancehall influences. Pioneered in the mid-90's by groups like The Prodigy and Meat Beat Manifesto (who still produce Breakbeat tunes today), other modern artists include Dillinja, Adam F, Speedy J, Aphrodite, and Goldie.

Breaks is a cousin of Drum & Bass, though typically with more of an emphasis on musicality, and samples of drum breaks from other styles of music. Where Drum & Bass finds its roots more in the caribbean, breakbeat owes more to electro and hip hop for its origins. Breakbeat tracks also typically have much slower BPMs than their Drum & Bass couterparts. Modern practicioners include The Chemical Brothers, DJ Assault, and Kingsize.

Hardcore

Hardcore pushes the boundries of dancable Beats-Per-Minute counts in music, often between 160-220 BPM. Hardcore's current incarnation is thought to have originated in Germany and the Netherlands in the early-to-mid 90's, and has a wide variety of sub-genres ranging from extremely dark Dutch Gabber to uplifting and pop-esque Happy Hardcore. Some artists include Adam X, Tron, Reyes, Delta 9, Brisk & Trixxy, and Vinylgroover.

Ambient

Ambient is the term used for most electronic music that has no steady beat. This style of music is thought to have developed both out of pure experiementation, and as music for so-called "chill rooms" at parties. Examples of artists include Aphex Twin, Orb, µ-ziq, and Spacetime Continuum.