Darkest Days is my favorite album of the 90's, beating the likes of Garbage, Curve, My Bloody Valentine, Nine Inch Nails, Skinny Puppy, and others. Stupendous. And HDCD to boot! Nice variety in the style of Pink Floyd and Dream Theater (though not progressive...it just has that deep, dark, quiet, understated stuff, followed by barrage of metal and synths). And you should be able to get either of their previous two albums really cheap, too.
The new, self-titled one is very good, too, though it's not as continuous as their previous one. It's more song-oriented. They must have taken some lessons from Garbage. I think it will be perceived as having less filler, though I wouldn't say DD has any filler. Wither Blister Burn & Peel is really good, too.