I can't believe I'm doing this, but I find myself trying out EVERY artistic iGoogle theme. ( I mean, I don't even use iGoogle!)
But they really have some nice sets! It's interesting to browse through different style world artists' works appear in this thin header of Google. And if you are looking for more artistic banners, here's a collection of some Amazing Banners with introductions of their designers.
Philippe Starck
Anne Geddes
Dolce&Gabbana
Pocoyó
Gustavo Rosa
Jean-Charles de Castelbajac
Edward Monkton