Just thought I'd throw this in rather than start a thread and be accused of homerism but I got this from the official Chiefs website:
3-0 Playoff Odds
Many of you have asked for the statistics, so here they are.
Over the last five years, 21 of the 27 teams to start 3-0 or better have made the playoffs. That’s a playoff percentage of 77.8%. What’s interesting, however, is that five of the six teams that missed the playoffs did so in the past two seasons.
Since 2005, these are the teams that have missed the playoffs following a 3-0 start…
2009 Broncos (6-0 start; 8-8 record)
2009 Giants (5-0 start; 9-7 record)
2008 Bills (4-0 start; 7-9 record)
2008 Broncos (3-0 start; 8-8 record)
2008 Cowboys (3-0 start; 9-7 record)
2006 Bengals (3-0 start; 8-8 record)
So according to this the worst we should do is 7-9 which is above most of our expectations before the year started.