Well, there are many names that sound very Scandinavian/German and the fact is, nazis liked those names. You can read more in
German about the laws nazis commited here:
http://www.beliebte-vornamen.de/deutschland1933.htm . I have also some kind of reaction when I see too many of those names paired together (Let's say a sibset
Hildegard,
Helga,
Helmut,
Hedwig,
Heidrun, Holdine - those were the names of Göbbels' children :D) - and that's the reason I try to keep always some kind of balance by pairing my favourite Germanic names with something Jewish, in some situation Slavic.
Runa is quite fine with me, very viking-ish. I really like
Ortrun, though.
I'd also try to remember many Jews had (and have!) Germanic names - in Soviet Russia, for instance, if you hear about someone named
Sigismund,
Emma or something like this, there's a big possibility he/she is a Jew. And don't forget
Albert Einstein,
Gustav Mahler...
Or... just take a look at this list:
http://en.wikipedia.org/wiki/List_of_German_Jews#Scientists
:D