Mayor Spencer sounds like a much better candidate than Pirro. If he could get elected and reelected in Yonkers, he might not do so poorly in Brooklyn and Queens and should do well in Staten Island, Long Island and parts of Westchester. He'd have to build up his name ID bigtime in Upstate if he is to make a real race out of it, but I don't think his issue positions would hurt him Upstate (as would be the case with Pirro).
One guy I thought might make a good challenger to Hillary was former Congressman Jack Quinn of Buffalo, whose only flaws as a statewide candidate would be (i) his potential inability to connect with NYC metro area voters and (ii) his apparent lack of interest in reentering the political fold. Spencer sounds like someone similar to Quinn in his conservative stances on social issues and ability to win in a heavily Democrat area.
Of course, as much as I hate to say this, our best shot at beating Hillary might actually be George Pataki (who has recovered from low poll ratings several times during his 11 years as governor). But he wants to run for President (snicker).
Quinn might've made a good candidate, but it is just so hard for those not in in the NYC media market to get an even break statewide. Upstate and the city probably should be split into two states.
As for Pataki, I think Hillary would crush him. She needs a tough and unapologetic opponent. Pataki is like a lumbering boob. It's similar to the problem that the CA GOP has, in that it hasn't put up a tough opponent against Babs Boxer since Conservative Bruce Herschensohn in '92. Meely-mouthed milquetoasts can't slay evil witches.