I think it's interesting how Ulver, Anathema and Katatonia are being mentioned. Each of these bands, while I love their earlier work, I think peaked when they perfected their own unique sound -
in the case of Ulver, with Perdition City
in the case of Katatonia, The Great Cold Distance
in the case of Anathema, Judgment or A Natural Disaster
Their 'classic' albums (Nattens, The Silent Enigma, Brave Murder Day) are all great but you can find better in their respective genres.