I must say, Fred Thompson gave quite a powerful speech--about as effective a case as you make for John McCain, at least without offending the party base. Thompson was a pitiably bad presidential candidate, of course: bizarrely unable to channel the qualities that make him a good actor into selling himself. But watching him tell John McCain's story--with skilled solemnity, emphasis, and dramatic pauses--it's hard to imagine who would have done this better. Perhaps like many actors Thompson is most comfortable in someone else's skin. I'm not sure which speech in this muddled schedule qualifies as a keynote but Thompson's has de facto filled that role.
Thompson made a fascinating reference to McCain's opposition to Reagan's troop deployment in Lebanon. The last thing you expect to hear at a GOP convention is a Republican bragging on his disagreements with the Gipper. It's a reminder to Americans that McCain hasn't always been a reflexive hawk--although it's certainly been a long time since we saw that side of him.
And it was more than a little rich to hear Thompson implicitly trash Obama as a star of the Washington cocktail circuit. Thompson lives in the tony GOP suburban enclave of McLean, Virginia. And Obama has done very little socializing around DC.