Stereolab has been recording music since some time in 1990. Their early EPs are characterized by a dense, repetitive (in a very good way) guitar sound, overdriven farfisa jaguar organ and two female vocalists, one the nico-esqe Laetitia Sadier and the coo-ing lala-ing Mary Hansen.
Their early EPs and releases are well represented by the Low-Fi 10" and Switched On, although there are other rarities.
Their first proper album, Peng!, is a must have for any fan. Their sound was so new at that time and very distinctive to this day. Surrealchemist, the last track on the record makes me cry.
After the first of several wonderful mini-albums, The Groop Played Space-Age Bachelor Pad Music, they released Transient Random Noise Bursts with Announcements This record was the first of several major changes in their sound. Transient... is more hard edged and experimental than their previous work. The stark beauty of Tone Burst opens the record -- here Laetitia's voice mixes with fuzzed-out guitars and, notably, the kind of melodic bass line that would become more and more prominent in their releases. Other notables: Golden Ball's eerie atmospheres, Jenny Ondioline and Crest.
The Jenny Ondioline EP was released from this session with the b-side French Disko, which with John Cage Bubblegum as its only real competition, has proven to be their most rocking and loud song to date.
Mars Audiac Quintet followed, with a smoother, more finely produced sound. Then Emperor Tomato Ketchup, which is my personal least favorite of their records.
Their more recent work has been well-covered here by other nodes.