Personally I prefer the Gas-the-Cabin route.
An aircraft is probably uniquely suited to this solution as it is a sealed container; all air supplies come via the packs; adapting these for the application of a quick-acting sleeping gas, CS-type gas - or even, for that matter laughing(!!) gas - should not be difficult and would both dibilitate any hijackers as well as enabling thier capture. Granted it may be unpleasant an possible even unhealthy for some of the passengers, but nothing like as unhealthy as hitting the side of a 110-storey building at 300kts!!
We already have quickly accessible gas masks; surely this is vastly better that the more blood-thirsty methods described above???