If you want to learn about German hip-hop, Die Fantastischen Vier are the group to know. Alas, no sanctioned MP3s on their official site, but the label they run, Fourmusic.com, has a great selection. You can find music by Thomas D, the Fantas' "Mikrophonprofessor," among others (many German hip-hop artists). Thomas sang "Wish (Komm Zu Mir)" with Franka Potente on the Run Lola Run soundtrack (also highly recommended by yours truly).

When Thomas isn't rapping, he writes rather thoughtful love songs such as "Liebesbrief" (Love Letter). (If you click on the name link above, you can listen to his other solo songs by choosing »Tracks anzeigen / hören on the page sidebars).

(Die Fantastischen Vier) Thomas D: Liebesbrief (single)