Afghanistan is going to get attacked no matter who is in power. The public basically demanded it. I'm pretty sure Gore wouldn't be going to Baghdad. McCain... maybe. He definitely has neocon overtones, but don't confuse rhetoric OTL with what he might actually do. But if he does, it'll be more competently done-no fighting the war on the cheap. Iraq is still going to be a mess.
McCain definitely has more freedom of action than Gore-toughness credentials are useful in times like these to keep away the hotheads. He'll be bloody. What he will do with Pakistan is interesting, given his pit bull reputation. My guess is he really doesn't care who runs Afghanistan afterward so long as they aren't a threat, so it'd be shorter.
Gore... Hm, he'd be under pressure for a tough response, so I don't think he would have the time to plan like McCain could, as mentioned. He would be more interested in nation building than McCain would be, so probably a longer effort. However, he also wouldn't be as aggressive with other nations, and would use the power of the Presidency (expanding with 9/11) to get stuff done.
Each have their pros and cons, but overall, better with either of them.
How Gore would approach Iran-is it possible that he might see an chance here-would be interesting. I don't think McCain would.