There is just something about pet and venomous snake being in the same sentence that makes me sort of weary, lol. Maybe a better way to word it would be "What venomous snake tends to make the best captive?" That's how I would have put it, but of course it's up to you. Anyway, to actually answer your question, my opinion would have to be boomslangs, Dispholidus typus. Booms have to be one of the most fascinating snakes on the planet. They are perfect display animals, as they are diurnal and more often than not can be seen cruising the branches of their cage. If I or anyone else ever walk into my snake room and my male boom is out and about, he will usually stop what he's doing and stare intently at me/us. There is a definite perceptible intelligence in this species. Also, unlike many other venomous snakes, booms tend to become quite "tame" in captivity (again, tame and venomous snakes are usually words I try to avoid using in the same sentence). I have never handled a boom that was out to tag me. In fact, even the very flighty female I acquired with my original 1.2 adults would only try to run, never becoming defensive. I'm sure their inflating display is very impressive, but I've seen it so few times and it's been so long I wouldn't know. In my personal opinion, the only dangerous time to be working with them is during feeding, in which case anything that moves is fair game and you must stay out of the way. Let's see...what else? Well of course there's their dentition. Boomslangs have probably the most mobile, advanced fangs of any opistoglyph (rear-fang). They typically have at least 2, sometimes 3 gigantic fangs on each side of the mouth. The fangs in an adult can easily measure 1.5 to 2 cm in length, which is enormous for a rear-fang. These fangs are very viperid-like, and can be swung out when in use, or folded back when not. They can also rotate a bit from side to side, which is why you have to be very careful when restraining one by the head. The fangs are the most forward placed than in any other rear-fang, basically right under the very large eye. The venom is insanely toxic with a very strange "Ebola-like" effect on its victims, melting from the inside outward within 24 to 48 hours. The problem is that no symptoms appear in the meantime, you just suddenly crash and die.
Now after all that you may be asking why on earth I say they are the best venomous snake to keep in captivity...well, they are just very neat to have and observe. Like I already said, they are usually out all day. During the breeding season, males will court females, using a very interesting and impressive bit of muscular control, holding the head perfectly in one position while "snaking" the neck. Females will respond to this either by doing the same thing back to him or by jerking in typical snake courting fashion. This muscular control will often be used while being handled; as in the snake will hold its head still while the body may be moving all over the place. I won't even get into the very strange aspects of their actual reproduction here.
Anyway, I could go on and on, but this the basic gist of why I considering booms to be great captive venomous. Though a bite from one could easily be fatal, they are incredibly reluctant to do so, probably a lot less than many of rear-fangs.
-Chance
River Valley Snakes
near death encounters) with hots who are still alive...but that doesn't mean they know what they are doing...
