1 SYSTEM OF A DOWN, Toxicity (2001) A new-prog masterpiece, blending metal with out-there funk, Middle Eastern melodies, leftist politics, and Zappa-esque absurdity, all within accessible pop-song structures.
2 COHEED AND CAMBRIA, In Keeping Secrets of Silent Earth: 3 (2003) A convoluted concept album, Secrets boasts churning guitars and high-pitched double-tracked vocals that sound like a more menacing Rush.
3 THE MARS VOLTA, Frances the Mute (2005) Careering from Latin rhythms to thrash to jazz, often within a minute or two (there are few real ''songs'' here), Frances explodes with energy and creativity. Challenging, but remarkably listenable.
4 LIGHTNING BOLT, Wonderful Rainbow (2003) Without employing any studio effects, this duo (a singer-drummer and a bassist) create a monstrous wall of noise that's a springboard for some seriously masterful improvisation.
5 THE DILLINGER ESCAPE PLAN, Miss Machine (2004) The heaviest prog album you're ever likely to hear: punishing hardcore with quick changes, incredibly complicated structures, and oddball antics.