I agree with regulation for most of the reasons mentioned here. Here's where I stand specifically:
-Kids under 18 shouldn't be able to purchase giant snakes or venomous without their parents signing off that THEY'RE the ones responsible until the keeper is 18 and understand what the animal is going to turn into when their kid decides they're bored with it or realize they can't take it to their college dorm with them. "Oh it's just a little snake in an aquarium" should never be a reason someone is allowed to get a pet. They should have to sign a document understanding that the animal will weigh more than they do at some point and be unsafe to handle alone (moooommmm, will you help me take out my 130 lb snake so I can pick up its turd that's larger than the dog).
-Some animals are not fit for pets. Please don't confuse that statement with saying people shouldn't be allowed to have them, they just shouldn't fit under a word like 'pet' and therefore should require some kind of screening and regulation of their keeping. Of all of the animals under the title of herps, I'd actually say monitor lizards fit my reasoning best. The main point of that reasoning is their intelligence and specialized needs, not their size or 'destructive powers'. Second on that list would be venomous snakes and third would be the largest constrictors. Those last 2 would simply be because I think they require specialized enough care that there should be a screening or regulation process behind keeping them, for the sake of the animal and not the keeper.
It'd be great to make people get a permit to have a human child but it will never happen - so that point is really derailing the thread or trying to compare an apple to an orange to make it look rotten. Its sound logic objectively, but not sound logic in the context of the reality of our society.