I think we can be optimistic. Often the momentum on Friday leading into the final weeking is quite telling. Two years ago we were hearing that Republicans were pulling ahead, and they made gains in Congress. In 2000 it was obvious Gore was gaining speed after the DUI dirty trick. And 4 years ago at this time I remember the consensus being that the momentum had shifted, and Republicans would not make the big gains in Congress they expected. So with GWB up in every poll, I think unless the Dems pull some other dirty cr*p, we should be OK.
I agree, though we now have a huge late wild card thrown in, now that it appears as though Osama is alive (something I was wrong about) and has decided to emerge to taunt America once again. It will be very interesting to see what kind of impact this has over the next couple of days.