The best traps are the ones you never see coming. I'd say like this one but it's fairly obvious that it's a trap. That said it's a good one. No one expects the elevator floor trap. Or any of the traps that a competent villain might install. After all the best traps are the traps that aren't traps at all. They're the ones like ambushes that you can't disable with a skill check. Of course there is advantage to be had if someone figures out there's an ambush, but the trap isn't completely bypassed. I do prefer traps that make sense for their location. Hideous death traps are all well and good for a tomb that is supposed to be sealed up with only the dead inside. Not so much sense in putting one of those in a major corridor for a base that is used with high frequency. After all you know someone is going to forget the trick to avoid the trap and then you're out a minion which gets expensive if you lose enough and does horrible things to morale. Thus alarm spells and things your minions are immune to work much better.
Art from WIN!