Let's see...
Great Britain
William will have an official girlfriend
Harry will become a professional Polo player (some else said this as well)
Peter Philips will get engaged
Lady Gabriella or Lord Frederik will be spotted with a serious boyfriend/girlfriend
Camilla will play a larger role at official functions with Charles
Greece
Prince Nikolaos will get engaged
maybe one more baby for Prince and Princess Pavlos
a baby in 2005 (boy) for Princess Alexia
Denmark
Frederik and Mary will announce that a baby will be born sometime in 2005
Princess Nathalie (daughter of Pss Benedikte) will get married
perhaps, one last baby for Prince Joachim and Princess Alexandra
Norway
CP Haakon and CP Mette-Marit will take on more official duties and if all is going smoothly with regards to King Harald's health then maybe they will have another baby in late 2005/early 2006
Martha-Louise will have a second child in 2005
Sweden
Prince Carl Philip and Emma will still be together
Perhaps Princess Madeleine will get married
The Netherlands
Magriet's younger boys will get married
Willem-Alexander and Maxima will have one more baby in 2006
Marliene and Annette will both have babies or announce that the stork will soon visit them
Monaco
Either Albert will get engaged or Andrea will be named his successor
Charlotte will have a serious boyfriend
Stephanie will have one last baby
Caroline and Ernst will be doing just fine
Jordan
Prince Ali will get engaged/married
Princess Haya will get engage/married
one last baby for the King and Queen
Spain
Felipe and Letizia will announce that a baby will be born in 2006
Jaime and Elena -- another baby