ALBANY, N.Y. -- Sen. Hillary Rodham Clinton is maintaining big leads over potential Republican re-election opponents, but she would not fare so well among New York voters if she faces Rudolph Giuliani in a 2008 presidential race.

That's according to a statewide poll reported Monday from Siena College's Research Institute.

The poll shows Republican former New York City mayor Giuliani leading the former first lady Clinton 48 percent to 42 percent among registered voters asked about a hypothetical 2008 presidential matchup.

In another possible 2008 matchup, Republican Arizona Senator John McCain of Arizona was favored by 46 percent of New York voters, compared with 42 percent for Democrat Clinton.

On the Senate re-election front against her potential GOP opponents, Clinton leads former Yonkers Mayor John Spencer 58 percent to 32 percent.

She leads Reagan-era Pentagon official Kathleen Troia "KT'' McFarland 58 percent to 28 percent.