To those of us who grew up in the Bay Area during the thrash heyday Slayer was an integral, important part of our scene. To us they were bigger than Michael Jackson, or U2, or any other big name artist of the 1980's. They were to thrash what Nirvana was to grunge, the quintessential band of the genre. I know Metallica was always more popular, but Slayer, to me anyway, was the best of the "big 4".
Really sad news, and hopefully this will encourage Kerry and Dave to realize how short life can be and reconsile their differences.