One Constitutional amendment I would like to see is the Presidential line-item veto. Clinton tried to do that once, and it was overturned as unconstitutional, so would need an amendment.

In terms of Supreme Court, or any other justices, they need to resist the temptation to be "judicial activists", creating the law rather than interpreting it. I have been pleasantly surprised by the moderate stance of Chief Justice Roberts, a Bush pick (although I don't agree with everything the Court has decided.)

Because the SCOTUS is a lifetime (or until the Justice decides to retire) it is somewhat decoupled from the other two branches of government. It would be even more so if all public offices had term limits (also requiring an amendment for which I'd be in favor.)

Regardless of what your opinions are, please go out and vote, all you US citizens out there in Pettalkville!