Who would be the best support for Summoner's Rift in your oppinion? Could you ponder their pros and cons?

Honestly, there is no such thing as the "best". Every support has their pros and cons, as well as amplified pros and cons with different ADC's. For example, Nunu has the ability to turn regular ADC's into hyper carries later on in the game. Soraka and Sona have sustain lanes capable of making the lane phase easy for weaker lane phase carries. Leona, Blitz, Taric have the potential to quickly net kills during the lane and can initiate team fights later on in the game.

So overall, I personally feel that each support brings uniqueness to the table and bot lane comps is a mini game in itself.

This is an extremely hard question to answer.

Frankly, its not about the best support, its about who best synergizes with their AD carry.

For instance: Janna/Graves work absurdly well together because he has natural armor/MR which make her shield block that much more.

Tristana/ Taric work extremely well bottom because his stun and her W makes it nearly impossible for a carry to run once they initiate.

Ezreal/Soraka work well together because EZ can spam his Q and lower his cooldowns on the rest of his spells.

There are tons more those are just a few of the bigger ones. If you're looking for a strong support people rarely complain about pick Blitzcrank. He's fairly tanky naturally as well one of the best utilities in the game. Though if you're bad, or have a bad game, people will let you know.

End game though, you need to find what suits you. Wait for free week supports to come out and try them. That's the only way to find any new champ.

If you have a good adc who knows what they are doing I would say leona.

Pros: Long range AOE slow
can initiate from a distance with her E/R and absorb a decent amount of damage with her W.
Her passive adds a nice amount damage to the adc damage
She and the adc can drop wards right when placed with her Q and auto atk
She has a stun and a grab and a slow... Tons of CC
Doesn't need to get boots early allowing her to put more gold into wards

Cons: If she doesn't hit her E to initiate she is slow to get into the fight
She only works well with a team who can capitalize on quick initiations
No lane sustain for her or the adc
No way to protect the adc (shields/heals) besides getting in the way of skill shots
She has to be played aggressively (Not sure if this is pro or a con. But since she doesn't have sustain she needs to get in there and make things happen)

while i agree with all of the above posters i also think it's all about personal play style as well. when not supporting i enjoy playing bruisers so Taric seems to fit my support style best. great lane support but tanky enough mid/endgame to initiate the fight and tank towers. as i said though, different strokes for different folks

oh well.. this question cant be answered.. all according to your adc and also enemies adc and supp.. like nunu kog works so scary :/ or somethin like taric tristana/vayne also works well.. too much combination and no one can be said the "best"

well it depends on your adc and your and the enemy team comp.
Ive tried various supports...
eventually i feel like soraka is just bad. Her heal is weak...her cc is weak...shes kinda squishy...she has no damage....I tihnk she was drastically overnerfed
I like lux...although she doesnt offer much for sustain..her harrass is fantastic...and she can also harrass safely(long range)...and light binding can very often refute ganks and such...and produce kills if someone tried to towerdive...her sheild is good enough, basically, for many situations...if you are good with it and quick on the draw you cna nulify lots of pokes...and i cant remember how many times i saved someone from dying from ignite. While lux keeps the enemy lane annoyed, the adc can farm in relative peace.

For sustain...i actually like kayle the most. I think she heals at least as well as soraka, while the movespeed buff seems more 'relevant' for a heal than armor buff...if a guy needs healign they might need to be getting away real fast. Kayle harrass is quite good also, and she can become another damage dealer fairly quickly and easily after the support laning phase is done. (suport lux transition is much mroe painful) THe kayle ult is also one of those clutch teamfight winners.

of course sona is a very strong support...and has a nice ult jsut like kayle..i played her some, but not much...so i just cant comment on her really. I have played her enough that i get the feeling i might rpefer her to kayle...but it annoys me that you never actually target anything with sona...shes so friggen easy

oh ive done support zilean some also...it would be quite good...if anyone ever noticed that you ulted them. They always keep runnign away. its frusterating.

Taric is always a solid support. Not knowing what my adc is going to be I always pick Taric. His kit is amazing and he's hands down my favorite support.

Ezreal and Raka are good.
Blitz and anyone is solid, assuming you can land grabs and they can capitalize on them.
Sona/Caitlyn is an amazing poke lane
Graves and just about anyone is really solid