So I ended up seeing about half of the debate, and I'm not really heartened by the result. Kerry seemed to be more communicative - despite constant annoying mention of Vietnam - than usual, connecting with the room. Bush kept stumbling, for long painful periods of silence; I think he must have been flustered by some of the weird accusations Kerry made.
Kerry has likely scored some points in small pockets of the undecided middle here. This is not good. But thanks to low expectations and existing preconceptions - we already know he's terrible with off-the-cuff oratory - Bush probably hasn't lost anything. This seems to be a draw.
On the other hand, I'm now eagerly awaiting the next debate more than ever.