2010. One scenario is the state GOP successfully recruits Trump to run in '06 since Pataki is getting out after 12 years at the helm; Spitzer gets the democratic nomination as in OTL. The only way for Trump to pull off a win is Spitzer's prostitution scandal coming to light early; Trump would be running in a midterm favorable to democrats after 12 years of GOP control in a blue state. Spitzer goes down to now Governor Trump who is entering office on the heels of the great recession, and has to contend with a state assembly now controlled entirely by dems after 2008 which goes pretty much OTL; which means state senate dysfunction is likely going to happen.
Enter a more jaded Hillary Clinton who thanks to butterflies refuses Obama's offer to be SecState and instead seeks to launch a comeback in 8 years time, ruling out a primary challenge in 2012 and would instead look to 2016 to either succeed Obama or defeat whoever might beat Obama in 2012. With Trump likely not handling the recession very well; Hillary sees an opportunity to cap off nearly a decade of Senate service and put possibly six years of executive experience under her belt before 2016 and challenges Trump in 2010. I think we can all assume that 2010 won't be the Democrat's year in general, but like in OTL a Democrat will still pull off a win in New York and we now have once again that unlikely match up of Hillary Clinton vs Donald Trump.
What 2016 holds for now Governor Clinton is anyone's guess.