I had a couple of time so i tried all of the builds above, 1 by 1.
I fount Evelynn AWESOMELY USEFUL!!! she can easily avoid early fights and just cpture points by using Shadow Walk and later in the game she kicksass!
After she has Trinity Force and a Vampiric Scepter she is just unstoppable!
Rammus was very fun to play with! we captured Windmill awesomely fast and i was annoying the hell out of the enemy (they had 3 melee and a tank+ a caster)...none of the melees are able to deal with you and i killed a Brandfaster than he could react!
Also very good at teamfights though.
Well Hecarim didnt became my fav... The problem is that he can barely escape the early harassment and they always focused me....He also has a great damage though but cant fight 2v1. Also very CC sensitive.

I loved this build though! +1

You've forgot to count with Sheen.And each champion has the 10% Armor penetration(hecarim has even more)
Now some calculating:(for lvl 18)
Evelyn has 205 AD so she does the criticals of 405 to 0 armor with one basic attack.Her Attack speed is 2.28 so it could be 810 damage a second BUT she has sheen so the 205 AD duplicates to 405 so one of her crits does 810 damage a second so its 1215 damage a second(because sheen can't proc twice a second) to 0 armor
Rammus does less damage but he has a very good defense and the cheat sheet does not count the passive AD bonus from armor.Also he has CC and a mass Shield.
Hecarim deals similiar damage like Evelyn but the cheat sheet does not count the 25% of that 417 mowementspeed ( thats around 90 bonus AD) so he has very big smacks and a good HP

you are immortal(dealing 800 damage a second
Hmmm.. How ? in that build i see something like 100 bonus ad. speed is limited to 2.5 .
So your crits will be somewhere as 300 max (cause I dont see an IE ) 300*2.5=750 . But it is not 750 true damage in mid game we will be looking at a damage reduction beetween 35%and 60% so actually your dmg will be somewhere near 300 per second ... Why don't you post a video usint this strategy ?