German rap is really very good. It's a completely different kind of rap than the usual gansta rap or soul stuff out there. Most of it is much more like the hippy hop of the late eighties that evolved around Dela Soul and Tribe Quest and such, but: big difference, all in German. Very laid back, nice poetic lyrics, no aggression, no bitterness, but a lot of fun instead (although the more recent stuff is getting a bit more in the face)
Besides Fanta vier (www.diefantastischenvier.de), there's the even more relaxed group Fettes Brot, that's Fat Bread (www.fettesbrot.de), which had a hit with "Ma'Sehn" ('ll See), and the now defunct & completely WACK duo Der Tobi und das Bo (they hide in some of these groups I believe), these two weirdos did songs like Mitdemfischanderwandindenputz (withthefishonthewallintheplaster).
Other way relaxed german rap bands include Fünf Sterne De Luxe and Absolute Beginner
Check amazon.de for online samples.