I actually would agree with Peter King's assessment right now. The Chargers have owned the Colts in recent years and have shown they can win this year. Close wins or not really doesn't matter. Closing games out matters in the end, regardless of the score.
The 2006 defense was scary good. The front seven could punish opposing offenses, and the corners were opportunistic and fed off the pressure created by the front. In comparison, I thought the offense was limited to the LT/Gates show, so take away them and the offense went with them.
The 2009 Chargers seem more balanced in comparison. Vincent Jackson, dubbed "scissorhands" by Cris Carter after his frequent drops in 2006, has developed into a good receiver. Rivers is much better, and you still have Gates. LT is not as big a factor, but I do not know if that is a plus or minus. The defense isn't great, but it is talented and athletic enough to balance out the offense and get the wins.
Given the recent performances by the Vikings and Saints, major injuries to the Iggles and the schizophrenic nature of the Cowboys, and the fact the Colts are not a balanced team and have frequently relied on the last minute drives to win games (thus one slow offensive performance and color them gone), I would have to give the Chargers the top spot.