[...]
I'd personally go for stock Gnome under Debian, but that's only because I could easily do that (by starting a fresh session and done). OTOH I guess distros like Ubuntu or Fedora have a more eye-appealing default theme, so…
I would say whatever is not ugly[1] and is easy, so long as they are all the same look.
Cheers Lex
[1] I havn't seen a default Debian Gnome lately and the project website has no pictures, so who knows.