I disagree. I think he will concede. But...what you have to remember is that a concession is not a legal act.
There are a handful of states where the electors are not bound by law to vote for George W. They can vote for whoever they damned well please. Those are the folks to watch over the next week, as those are the folks who can be threatened, blackmailed, bought, or whatever, to change their electoral vote to Gore. And the scary thing is that he needs only find 3 of them. And since a concession is not a legal act, legally it means nothing. The electors can still put him right in.
Even if Gore concedes tonight, it won't be over until January 20.
Just my opinion.