Goldwater wasn't a liberal. He was maybe a libertarian, but not a liberal. Have you read Conscience of a Conservative? Great book.
Yes, Goldwater was a libertarian above all. He was an ardent defender of liberty as one of his most famous quotations made clear. Goldwater was a great man who, unfortunately, in his very senior years made statements that appeared to undermine his conservative credentials. But, he forged the way for Reagan. I accept the common wisdom that he fell under the sway of the nurse who became his second wife.
Rehnquist was a great Chief Justice. Fair, an excellent administrator of the court and a champion of the principles of federalism that form the foundation of our government. He is only surpassed by his idol, John Marshall, who, unlike Rehnquist, was able to forge majorities and unanimity again and again even with Jeffersonian appointees to the Court.
As to Judge Roberts, he is a brilliant but mainstream jurist with conservative leanings from what we have seen.
What I look for most in a jurist is the ability to evaluate arguments and to apply principles of law to fact in a manner that is faithful to the Constitution. His statements about stare decisis are pretty standard. If you look at Supreme Court opinions, one could conclude the Court has always been engaged in correcting the decisions of earlier courts. It is a soft concrete on which the Court treads.
If I were on the Senate Judiciary Committee, I would ask Judge Roberts what books are in his library and what books he thinks have influenced him the most. I would ask him what he thinks are the most important decisions of the Court in certain segments of time and why. I would also ask him about his judicial philosophy on the assignment of opinion writing. That is perhaps a better indicator of how he will confront problems 20 years hence than intricate questions about the Voting Rights Act.