DEVOLVED. They have sound a bit like early Fear Factory but harder, faster and unrelenting. The vocals are bit like Jens Kidman's from Meshuggah. The drummer seems to steal the show though, with excellent double kick. In Distorted, the most popular song, he keeps up constant double kick for a minute straight, 2:00 onwards. Listen to Progress too. There is brilliant vocals around 1:30-2:05. Give Fallen Cities and Emergence a listen too.
Some samples at http://www.devolved.net but you should be able to find all their songs in KaZaA, with a bit of patience.

MESHUGGAH. Masters of death metal with great thrashy vocals. They use uncommon and abstract time signatures though, which probably groups them into math metal. A few of my favourite songs are New Millennium Cyanide Christ, Future Breed Machine, Sane and Humiliative.

BLOOD DUSTER. Best described as Porn Groove Death Metal. Catcy riffs, some of the best metal vocals around and very amusing lyrics and song titles like 'iloveitwhenjoepesciswears', 'don'tcallmehomeboyyac*nt', 'Knee deep in menstral blood' and 'Givin' stiff to the stiff'. I suggest to listen to Metal As F*ck, Pornstorestiffi, Northcote (features Skitz, Damaged's drummer) and The Corpse Song.

DAMAGED. One of my favourite death metal bands. They have a brilliant drummer, Skitz, who has some of the fastest feet around with extremely quick bursts. The singer looks a bit like an Elvis inpersonator but still sounds good.
There are some samples on these websites
http://www.intoannihilation.com
http://damagedcore.com/downloads.php
The songs are a bit hard to come across in KaZaA but try to get Nails.

DARK TRANQUILITY. They are melodic black metal, a bit like In Flames and Children Of Bodom.

PIG DESTROYER. Extremely fast, quick and heavy. Brilliant lyrics and great screaming vocals. Their album 40 Counts Of Battery consists of 40 songs that go no longer that 1 minute. Give Piss Angel, Naked Trees, Deflower, Suicide Through Decay and Flag Burner a listen.

THE BERZERKER. Seizure enducing songs. Good for a listen every now and then or good for annoying people who listen to Top 10 Pop crap. Massacre, Forever, Cannibal Rights and Corpral Jigsaw Quandary are my favourites.