I was just in Istanbul last fall, and it is fantastic and booming at the present time, and it's still on the affordable side of expensive.
Could not disagree more with the cruise idea - you never really get to learn a foreign culture when you only stop in port for a few hours. If on the other hand, you just want the lap of luxury and want to pamper yourself with midnight buffets and champagne - go for it, but don't call it "seeing" Europe!
Methinks you need a good travel agent - damn few around these days!
[ Edit: Edited on 29-Jun-2012, at 21:02 by Daawgon ]