As the Title suggest: Which evolution cycle stands out towards you?

I would say snorunt because it starts off with a cone-like figure than it can either evolve into a Giant Angry ball or a human-like ghost. 

In my opinion, the most interesting of the Pokemon evolutions would have to be Magikarp evolving into Gyrados simply because of what it starts out as and what it becomes. It tunes from a weak little fish into this giant dragon like thing.

I would have to say Snivy's evolution cycle stands out to me the most. Its evolution cycle starts off very slow and you can see the little changes that aren't very drastic like most Pokemon evolution cycles. The main biological appearance of it is still there in overall but seeing the tiny changes with body parts are very interesting like a realistic evolution cycle.

I'd have to say Eevee. Why? Because it represents genetic diversity, and might be the only pokemon that actually "evolves" and doesn't go through metamorphosis.

Cradily is love : Such Sophisticated  responses. I like how everyone thinks here!

I have to say ghost types and psychic types

For me the most interesant pokemon evolution will be probably

Flygon, why? because is a dragon who evolutes from an ant

it's sounds odd saying it now, I think

The most interesting evolutionary chain is Bagon's. I don't even get how a mini T-Rex evolves into an armadillo-like thing(Shellgon), which evolves into the almighty and powerful Salamence.

the most interesting pokemon evolution is gible.
looks like a shark but not water type actually.
but gabite looks a real shark dragon and when it evolves to garchomp beast shark dragon to me

I think Eevee's evolution is most interesting, since there are so many Type-Evolutions. I also like Eevee and I do enjoy playing with some of the Evolutions of Eevee as well.

Although I do not use Slakoth, I do think its evolution line is quite special because of the Truant ability (not so great by itself). He loses it as a Vigoroth but regains it as a Slaking. 

I also do find the Nincada line quite peculiar. If you have a party slot free, it will evolve into Ninjask while leaving a Shedinja behind. What is the science behind it, I wonder.

I would say Dratini to Dragonair and Dragonite. It starts out a small snake looking dragon and when it evolves from Dratini to Dragonair, not really a lot really changes look wise. It does get bigger and a few physical features change but not really a ton. When it evolves from Dragonair to Dragonite it really changes up. It gets legs, feet, arms and it even changes color.  It looses its beads that it gets around it's neck and tail that it gains when it evolves into Dragonair and it also looses it's horn. It looses it's ears and those get replaced with the little umm.. i am wanting 2 say tentacles but i am not sure that is what those are on it's head. Any way, even Dragonites eyes become smaller. That is why i find the evolution of Dratini most interesting. Second would have 2 be Eevee because of how many different types of pokemon it can become, most of those evolutions has 2 be done by a stone tho. So that is why i give the biggest change to Dratini and not Eevee.

Thank you all for your opinions. this helps me in my own goal of how to catch the interest of the consumer

*Giggles*
The... The Diglett chain.
And, the Magnemite one...
GameFreak knows what's better than one.
And that's three.
(At least they can count better than Valve.)

 Shuckle I mean just look at the evolutions it has. It starts out as Shuckle and just stays Shuckle the almighty. Which is why it is the best evolution cycle.

(Truly the best one is eevee though.

I'm with Zander on this one. I think that the fact that a pathetic fish like Magikarp that only knows how to use splash, tackle, and flail can evolve into such a ferocious sea serpent! It's hilarious if you think about it.

I don't know on Magicarp, I mean in my opinion Onix evolving into Steelix is far more mind popping, a Ground/Rock type ends up dropping the Rock side of this and becoming a Ground/Steel, I meant not only that, who would think something already so big practically double in size, and Onix is a dark grey colour as Steelix is more silver...so I'm on Onix to Steelix evolution

I agree with Dark sword Z's opinion on the Flygon evolutionary line. I find the colors from Trapinch to Vibrava to be incredibly strange, but it makes sense from Vibrava to Flygon. I just wished that some trainers in 3rd gen ever used a Vibrava because I would never have guessed that would be their evolutionary line.