Debian Deutschland e.V. makes potential re-use easier, else it's just a name of no importance. Toss a coin?
After the question simmered some more at the back of my head, I think I am leaning more strongly towards Debian Deutschland e.V. as it's the stronger brand name.
IMO, this will help with sponsorship hunting. If you've never heard of us before and need to decide if it's worthwhile to give us money, you will find more impressive stuff with Debian than with DebConf.