Actually I live in Germany, I don't really like most of the german rap (it just sounds ridiculous most of the time), but ive heard 2 or 3 songs of Clueso and I didn't really like him......
Check out 'Adriano (Letzte Warnung)' (means: Adriano - Last Warning) from 'Brothers Keepers', it actually sounds like dark, grimy QB-Rap but is actually a song about this african-german (?) guy who got murdered by racists in Germany in 2001.
Its really a track that gets you into german rap, imagine CNN in 97, but less gangsta, less thug, but down-to-earth and still dark & grimey and with some singing in it. Some english parts also in it, they collaberated with some UK reggae singers for it back then. Make sure you get the 7 Minutes long version.
Then, check out tracks like "Jein" from Fettes Brot or "Dreist" from Samy Deluxe (hes black, so dont wonder why he uses the n word so freely). Btw if you just want to freak out, d/l "Schwule Mädchen" from fettes brot
translated it means "Gay girls"
edit: listen to some Fort Minor. and im NOT meaning his album, which sucked pretty much. I mean his "We Major" mixtape with dj green lantern. You will all get blown away, the beats are the best you heard in a while and all these rappers like S.O.B., Apathy, Ghostface etc. are just killing it. Go and down... uhm, go down to your local store, i mean.