For me, the Marquee players need to cover spots where Australia doesn't have enough depth.
Lock is one for mine and I would think seriously about Hooker and Centres. There might be a bunch of Aussies running around with 12 and 13 on their back, but we still need to unwrap Gits out of his French cotton wool to have a competitive midfield. I can;t think of anybody in Oz who I'd want to be showing Kyle the ropes, but there are some great 12s and 13s internationally who might be looking to test themselves in Super Rugby...it would also serve as a pretty bloody big carrot for Godwin to stay and play with the experience of a Brian O'Driscoll, Jean DeVilliers or Conrad Smith showing him the ropes.
(OK, maybe somebody who hasn't retired, but you know what I mean!)