Chemical Brothers: Surrender. Probably in the minority with this one. It's a classic album, but most people prefer their first two offerings (which are also well worth a look in).
Andy C: Nightlife 1- 3. Every good dance collection needs some good ole' drum n bass (the more the better really!).
Squarpusher: Big Loda. Classic from start to finish. In fact, just get all the Squarepusher stuff that you can. The man is the defenition of genius.
Daft Punk: Homework is a must, as is Human After All.
Orbital: Orbital 2.