The Only Ghost Family

In Gen I, they totally missed their potential as a Psychic type counter, which is why the Psychic type was completely broken back then. But they quickly recovered after that. Personally, I haven't used a Gengar before, and I prefer Haunter's design over Gengar's. Haunter just looks more menacing to me. But Gengar is a big fan favorite, and I do like its Mega Evolution (especially its shiny form :O ).
The Ghost type has always been one of my favorites, and it's by far the least common type of all. Each generation only comes with a few new Ghost type Pokémon, which makes it extra special

 

Ghost is one of my favorite types. I've never really used a Gengar during the plot run of a game as I didn't start using WiFi until BW, but he's on my competitive team. I'd say that since they were weak to Psychic types, the introduction of a pure Ghost in Gen II was a way to counter that weakness, even if the introduction of the Dark type made it somewhat unnecessary.

 

Most ghost types are amazing and it's thanks to Gastly/Haunter/Gengar that they exist and although they weren't very usefull in gen 1, they sure are now.

 

They seemed to be the most iconic of ghosts, since the next generation, there was only one other ghost added to the mix (Misdreavus). I like how they kicked off with the initial concept of a ball of poisonous gas. They could have gone for just a generic ghost like Misdreavus but they really did something creative. I too like Haunter over Gengar, but I evolve them all now. The first Pokémon I caught in Soulsilver was a Gastly, and I accidentally bred it by forgetting what Dittos do. Since then I've been trying new move combos with Haunter and Gengar.

 

I actually really liked Mismagius quite a bit But yeah, it's a great thing that it got an evolution.

 

I think their purpose as psychic counters was not executed terribly well, but their introduction and association with Lavender Town were extremely effective and definitely scared the wits out of me as a kid. For a long time after I associated the colour purple with ghosts...

 

I feel like though they heavily influenced how ghost Pokémon are now, the fact that they were also Poison type made them incredibly useless in Gen 1. Alakazam was terribly OP compared to gengar, so the ghost Pokémon of Gen 1 were kind of irrelevant.

 

Though Ghost isn't exactly one of my favorite types, I have to say that Gengar was still my favorite out of the three.

Even though Haunter looks more menacing, something about Gengar just makes me like it better.

Psychic was way too overpowered in Gen 1. The only weakness it had was Bug, and the strongest bug move at the time was Twin Needle, with a whopping 40 power, and could only be used by Beedril.

Thank Arceus Game Freak changed up the type chart.

 

Some people said that Gengar mostly got screwed over by its typing in Generation I, while its moves weren't bad it could still be hard to use. But I think they took from that to make other Ghost-type Pokémon with more utilities to use or more balanced stats. Come the physical/special split was when certain Ghost-types got way better with Shadow Ball being special.

 

I never really used the Gastly family, or any other Ghost types in any later games, considering I was turned off by the fact that Ghost moves don't affect Psychic types in Gen. I. Even with that type match-up corrected in Gen. II onwards, I never really used Ghost-type Pokémon very much for very long.
Regardless of the generation, the Gastly line was already at a huge disadvantage against Psychic from the get-go, as well as Ground, due to being part Poison.

 

I found them creepy and mysterious in R/B/Y and was puzzled as to how to evolve it into Gengar but with no luck. They had a very cool design.

 

I think that they have fairly solid designs, although it was a shame that the only damaging Ghost-type moves back then did either a set amount of damage or very minimal damage. Psychic was kind of broken back then thanks to them, but thankfully Ghost has evolved as a type, and now has a very wide selection of Pokémon and moves to choose from. It's nice to look back on the Gastly line to see where all these awesome Ghosts came from, and now we even have Mega Gengar as a huge powerhouse in the new games, as well!

 

Originally, I believe they were just meant to be a gimmick type, but then, GF saw their growing popularity and decided to slowly add more to the roster as the Dex expanded.