So just below I posted on how I thought an advertisement by McCain during Obama's speech was inappropriate and disrespectful. I would stand by that statement unless this is the ad that is going to be played:
Whether McCain wins or not, taking time out to congratulate Obama on being the first black nominee for president should be remembered as a classy move.
McCain has been strong enough with "negative campaigning" that I don't think anyone will criticize him after the election for being soft, whatever the outcome. But an ad like the above is well-played and well-timed. It also preempts any sort of shenanigans during the RNC.