JoAnn and Pat, I wish we could do either TUT or Sydney to Auckland but the dates will not work (however, after my daughter graduates in June 2012 I shouldn't have that problem anymore!).
Priscilla, some of the ports are repeat for us too but like you we haven't been to Istanbul so that's part of the attraction. No time like the present to do that onboard booking! ;)
Diane, an Alaska cruise sounds like the perfect graduation present. A crossing is also in our plans once we are more flexible with our dates. We enjoyed tremendously our Voyager crossing in the Fall 2007.