Today the U.S. Supreme Court decided the case of Snyder v. Louisiana, No. 06-10119. There were 5 black veniremembers in the 36 who survived the for-cause stage of jury selection, and the prosecution peremptorily challenged all 5. That looks bad, even when it's justified, and the prosecutor needs to have good reasons ready. In this case, the prosecutor's reasons for challenging one venireman were that he looked nervous and that he was concerned about missing class. The Supreme Court held, 7-2, that was not sufficient, despite the trial judge's acceptance of the explanation.
Note that this case arose on direct review, so the habeas deference standard of 28 U.S.C. § 2254(d) is not involved. However, this case is now "clearly established" Supreme Court precedent, and it will surely be cited in most Batson cases from this point onward. Note at page 6 of the slip opinion that the Court is unwilling to presume that the trial judge relied on his own observation of the venireman's demeanor without any statement from the judge to that effect. Once again, we see the importance of making the record.