Unlike the surreally hyped scares that get rolled out hereabouts whenever the Bushies get bored, this business in Germany appears to be the real thing -- an actual, competent terrorist cell in an advanced stage of plotting an attack.
However, one aspect strikes me as rather strange. With a whole universe of easily obtained explosives, why on Earth were these guys stockpiling H2O2? In low concentrations hydrogen peroxide will disinfect wounds or bleach hair; at high concentration it's a potent oxidizing agent of many uses, but the closest it comes to exploding is occasional use as a rocket fuel component. (See for instance John Carmack's hobby.) Sure, you probably could build a peroxide bomb -- you could build a bomb based on lighter fluid, too -- but when there are much more potent substances more readily available, what's the point?