The updated Gallup and Rasmussen tracking polls for August 30th showed no change in Obama's lead over McCain (at eight and four percentage points respectively). Because these polls were taken the day after Barack Obama's acceptance speech, one may conclude that Obama received no bounce from his well-received speech. Since the morning of August 30th was when Sarah Palin was named as McCain's running mate, one may also conclude the polling results suggest that McCain successfully stole Obama's thunder and counteracted the positive impact of Obama's speech. Further movement in these tracking polls towards McCain over the next several days would suggest the positive impact of Palin on McCain's fortunes.
My own model showed no change from the previous day. Obama's lead remains at 50.9% to 49.1% and his Electoral College vote margin remains at 304-234.