Nate at 538 says:
The largest remaining scheduled moments in the campaign between now and November are the conventions and the debates. Is there any doubt that Obama is going to deliver a better convention night speech? Is there any doubt that, the first time he and McCain appear on a stage together, the contrast in age, height, and tone is liable to be pretty striking?
That's right in terms of convention speeches. So far as the debates go, I think the most noteworthy thing is that neither McCain nor Obama is very good at debating. To my mind, that's a stark contrast to 2000 and 2004 where we had matchups between two good debaters. I think this mostly reflects the fact that though debates are interesting media moments, they probably don't matter very much to outcomes, thus even though neither Obama nor McCain was especially impressive in their debates, they secured their respective parties' nominations. My suspicion, though, is that an Obama-McCain debate matchup will be really horrible to watch.