When I first heard "Du Hast" in the mid-90s, I kind of wrote it off as novelty metal. When I tell friends I'm a big fan, they often laugh based on the same assumption. I initially took the song at face value: a metal jam about being hated, pretty standard fare. However, one day a friend said that one could interpret "du hast mich" as either "you hate me" or as "you have me". This ambiguity turns the song into a much more emotionally complex piece of art. It also gives perfect context to the definitive Rammstein sound: heavily palm muted rhythm guitar juxtaposed against new wave keyboard melodies. These two sounds are great complements, and they keep drawing me back to this band, because we don't often hear them played together this well.
I often point to Depeche Mode as the biggest influence on Rammstein's music, which sounds strange at first. However, their cover of "Stripped" shows that they're coming from the same place as DM with respect to dark sexual imagery and powerful synth lines. Similarly, "Ich Tu Dir Weh" (from their 2009 album) is based around a soulful chorus and breathy, teasing verses that would make Dave Gahan proud. DM's bigger guitar jams - "I Feel You" comes to mind - would fit easily on a Rammstein album, and I could definitely see DM doing "Engel" or "Haifisch" quite beautifully.
There's one song to which I keep coming back: "Keine Lust" from 2004's "Reise, Reise". Besides a fantastic video featuring the band dressed up as dramatically obese versions of themselves, this song is sparsely and sharply constructed. We hear the giant spaces between guitar riffs, and the drums are pure and heavy. Alien-sounding synth licks hide at the ends of a few bars for the first part of the song, but in the 2nd half they jump up and round out the vocal performance, so the climax and coda are pure headbanging bliss.
I got to see Rammstein live in Cleveland in 99, and it was a wonderful spectacle. Lead vocalist Til Lindemann is giant and beautiful and expressive. At various points through the night he shot flames from his hands, feet and head. He jerked off a giant dildo and sprayed the crowd with it. He felt up every member of the band and headbanged to every song. He was like the Terminator, but with soul - easily the most energetic person in the room, and I would jump at the chance to see this band again.
The thing that really sets this band apart is that while they draw from dark and often depressing themes and images, the music is really quite poppy (especially for a German industrial band). This music invokes demons, and then faces them down without fear or irony. They've got the grandstanding of the best arena rock bands, but the dark, gruff sexiness of the best gothic glam bands. Four albums out from "Du Hast" with another due out in 2014, Rammstein has shown me that not only are they not a novelty act, but their unique sound continues to make their music fun and satisfying.