McCain use to be in the middle, however since the nomination he has gone to the right.
Lieberman is slowly becoming more to the right on certain issues but he's not a centrist.
Giuliani use to be a Democrat first but he is certainly has his many Republican views. He agrees with Bush on the War in Iraq, believes Iran has similar goals to Osama.
Political positions of Rudy Giuliani - Wikipedia, the free encyclopedia
Giuliani has supported Bush's tactic of using domestic surveillance. He also is a support of the Patriot Act. He also supports Waterboarding.
I will admit he has more Liberal views on things like Abortion, Stem Cell Research, Death Penalty.
With Rudy it's very back and forth on his views for certain things too.