Sununu, didn't know he had a 100%. Gawd that seems quite high for him.
Sununu is fairly conservative, but he isn't as conservative as Santorum. The problem with some of these ratings systems is their are rather selective in the votes that they use. If I'm not mistaken the ACU uses something like 24 or 25 votes over a year span. Kyl is someone else who I wouild say while being conservative is less conservative than Santorum.
This is wjat I would say is the top 10 as far as most conservative
1. Coburn
2. Bunning
3. Inhofe
4. Cornyn
5. Demint
6 Santorum
7. Brownback
8. Lott
9. Frist
10. Thomas
Edit forgot Brownback