The two most interesting issues seem to be "the constitutionality of requiring voters to show a photo ID before they may vote (Crawford v. Marion County Election Board, 07-21, and Indiana Democratic Party v. Rokita, 07-25)" and "the constitutionality of execution by lethal drugs when the chemical protocol poses a risk of pain and suffering (Baze v. Rees, 07-5439)."
ADDED: More on the photo ID case:
In general, Republicans argue that identification laws reduce voter fraud, while Democrats oppose them on grounds that they lower the turnout among people who tend to vote Democratic.
Coincidentally or otherwise, the two Seventh Circuit judges who voted to uphold the Indiana law, Richard A. Posner and Diane S. Sykes, were put on the bench by Republican presidents (Ronald Reagan and President George W. Bush, respectively), while the one dissenting judge, Terence T. Evans, was elevated by President Clinton.
Writing for the majority, Judge Posner acknowledged that the Indiana law favors one party. “No doubt most people who don’t have Photo ID are low on the economic ladder and thus, if they do vote, are more likely to vote for Democratic than Republican candidates,” he wrote.
But the purpose of the law is to reduce voting fraud, “and voting fraud impairs the right of legitimate voters to vote by diluting their votes — dilution being recognized to be an impairment of the right to vote,” Judge Posner said. And assertions that many people will be disenfranchised, or that there is no significant voter-fraud problem in Indiana, are based on unreliable data and “may reflect nothing more than the vagaries of journalists’ and other investigators’ choice of scandals to investigate,” the judge held.
In dissent, Judge Evans wrote that the Indiana law imposed an unconstitutional burden on some eligible voters. “Let’s not beat around the bush,” he wrote. “The Indiana voter photo ID law is a not-too-thinly-veiled attempt to discourage election-day turnout by certain folks believed to skew Democratic.”