On this very same day 4 years ago, Gallup said that Al Gore was leading George Bush by 10 points. A little over a month later, a couple weeks before the election, they claimed that Bush was leading Gore by 13 points. In the end, Gore won by a small percentage. It's not over til it's over.
As far as the stuff about Kerry not going on the offensive, I'm guessing you didn't see his speech today. Read it hear:
http://releases.usnewswire.com/GetRelease.asp?id=36502
I think Kerry could do a better job of utilizing the media. He needs to settle on a talking point or attack and repeat it until it sticks. There are so many ways to attack this president, its easy to get into the trap of just listing all his mistakes. This doesn't play well in the media though.
I think the debates are where Kerry can really do some damage to Bush. This is when he can force President Bush to answer the questions that the media doesn't want to ask.