Really, the debate here is between Arbok, Weezing, Muk, Nidoqueen, and Nidoking. But poison type Pokèmon are pretty cool. Though there's hardly enough of them. I personally prefer Muk. But I could see the argument for almost any of these. I do like Koffing, but Weezing is a bit of a weird tumor amalgamation. What do you think?

Yes! My element!

I don't think you realized in time, but my boys Venusaur and Gengar are poison type. More than a fifth of pokemon at the time were poison types for frigs sake. I'm one of those people who actually picked Bulbasaur, the thing is actually a beast these days, maybe in early gen not so much, since *pulls up documents* yep, back then solar beam constituted as what the devs intended to be the grass type ace in the hole. Now with actual moves at its disposal and a freaking mega I love Venusaur plenty, as for gen 1, well, Gengar doesn't learn any relevant moves outside TM's and isn't very... poisonous, so I guess I'll stick with Tentacruel and Weezing. For one, Tentacruel is a good specially offensive and defensive pokemon in gen 1, cause, you know, broken stats, and just generally tanky in any other instance. They make use of it with access to hydro pump, ice beam and blizzard, even mega drain and the unholy wrap of death. Maybe I like the idea of exploding in the faces of my enemies a bit too much, but Weezing is really tanky for what it is. That's a poison type's benefit in general, outlasting the opponent while setting up more and more ways to hurt them in kind. Really though, poison types really needed the tools given to them in later generations. As a bonus notice, Crobat is another favorite pick of mine. Poison flying comes with three quadruple resistances, and the pokemon itself is an excellent fast switch-in. That and Zubat are as common as lint.

You dug yourself into this hole, now run before I begin talking about Venomoth.

Mecha Leo : See, but they weren't pure Poison types. I was just going by a wiki post.

Definitely Weezing, since in Gen 3 he's a tank that explodes. Very nice for the Battle Frontier as a insta-kill nuke.

Probably Venomoth. It is a very under appreciated Pokemon with access to the single best boosting move in the game, Quiver Dance. Its Tinted Lens ability makes it hit even Pokemon that resist its STABs very hard after a boost and with access to Sleep Powder you can set up even more.

Plus I just like its design in general. I don't know when I started liking it but I think it was when I used it in a Nuzlocke once, which is how I come to appreciate most of my favorite Pokemon.

I feel like I'm going with the generic answer, but I love gengar. It has a fairly plain design but I feel like it can be well used as a mega. And have you seen shiny Gengar? It literally looks like a ghost. I normally catch female ghastly and name it Vespertine due to an old tradition with my pokemon.

My favorite poison type from gen 1 would have to be Victreebel. It's the only grass/poison dual type I've ever really enjoyed using. It was a powerhouse back in gen 1.

For Gen 1 poison types, I would probably have to go with Nidoking. Even though it isn't a pure poison type, I also really like the design of Haunter as well. It looks much cooler and far more menacing than Gengar, which just looks like a fat little munchkin. I like the way Haunter floats and has hands that are completely separate from its body. Gengar just doesn't look as cool to me. Its shiny mega form helps with this quite a bit though.

My favourite gen 1 poison type would be victreebel, since it is also part grass I find that it can cover both typings rather well in my opinion which is always a good thing. That and it is also a really solid pokemon across the board in my opinion.

I'm going to have to go with Weezing I grew up with the OG anime thanks to my mom so I always liked Team Rocket when James had one and I always liked James more then Jessie.