The Element of Magic? DUH.

^Exactly! She's the Element of Magic, if she wasn't the most magical, than she wouldn't be worthy of that title.

Go Twilight! She's very powerful!

this was a no brainer1 of the 6 elemints of friendship? this wass an easy question

even though Celestia has enough magic to send someone TO THE MOON, Twilight is, of course, the element of MAGIC. Although, since Celestia used to be able to use all of the elements of Harmony Single-hoofedly, including the element of magic, wouldn't that mean... alright, changing answer to celestia.

Also, Celestia has lived for over 1000 years. Her magic must have built up to a substantial amount over the LONG time she has lived. Who knows what she could be capable of... besides the whole TO THE MOON stuff.

And for another thing, correct me if i'm wrong, but isn't the size of a unicorn/alicorn's horn supposed to show how much magic they have or something?

Edit: meant unicorn/alicorn's horn. my bad

Really obvious Twilight she has the element of magic so practically that means she has the most magic

Well, it's either Twilight or Celestia. Element of Magic representative (though I wouldn't necessarily think that means that she has the MOST), or seemingly all-powerful god-queen. Both have a fairly strong case based upon events in the show. :/

And I'm not sure about the size of an Alicorn or unicorn corresponding to their degree of magical power. Hmm. So they would grow larger if they gained substantially more abilities? I simply figured that Alicorns--apparently--tend to be very tall ponies, and obviously the only ones we know of so far ARE supremely powerful. They're immortal god-princesses/queens, for corn's sake. There may be a relationship between their power and their larger stature (certainly feels appropriate), but is it a coincidence that Luna is smaller? Well, who knows? I guess that size thing may hold true for Alicorns, but I don't believe it does for anypony else...

I've noted that Alicorn horns are considerably longer and thinner/narrower than normal unicorns'. This, I presume, is both part of their anatomy and genetics, as well as an indication of great power.

@btflash: yeah I agree what u said

Oooh, hold up for a sec! I just read character descriptions in the little booklet that came with my latest pony figure, and according to them, Princess Celestia is "the most magical pony ever!" Sooo, if ya wanna take their word for it...it's still a bit of a toss-up for me...:/

Oh YOU FORGOT! *Turns Grey*

No doubt about it.

My answer contains spoilers if you have not seen the episodes Boast Busters, The Cutie Mark Chronicles, The Return of Harmony, and A Canterlot Wedding.

I think its either Twilight or Princess Cadance (I know she's not one of the choices , but let me explain). The reason I say this is that is it seems Celestia is getting weaker in her old age.

Here's my reasoning for Twilight: Princess Celestia said in the Return of Harmony that she and Luna can no longer control the elements meaning that mane six especially Twilight have become more powerful than both of them. Also in The Cutie Mark Chronicles Princess Celestia commented on Twilight's magical abilities saying that her raw power is stronger than anything she's seen before. As far as Trixie is concerned I think Boast Busters did a good job showing Twilight is more experienced. And going back to Princess Celestia I do think that at one time she was stronger than Twilight, but as of right now I think her power has diminished.

Here's my reasoning for Princess Cadance: A Canterlot Wedding made Celestia seem like a helpless princess. Her powers barely even grazed Queen Chrysalis. And who beat Chrysalis? The love of Cadance. Cadance's magic is love and it was what banished all of the changelings. So I think she too could be the most powerful.

Now I won't be sent to the moon,

@KotokoAihara: The reason Celestia and Luna can't use the elements of harmony any more (at least I believe this is true. I read it somewhere, but I can't remember where) is because the elements of Harmony have been passed on to their new "Masters," so to speak, and will no long accept Celestia or Luna as their Masters.

The Elements of Harmony (read this somewhere, too. This means I don't exactly have "proof," but you can take my word for it if you want) change shape according to their new masters, and will only accept their current masters until they change form once more to accept new masters. I don't really think it has anything to do with magic ability.

Also, I've read a few fantasy novels to know that most magic doesn't diminish over time; it strengthens. There might be a few cases here and there, but I'm sticking with my choice of Celestia being the strongest. The only reason she couldn't defeat Chrysalis was because Chrysalis gained an incredible amount of power from the love Shining Armor has for Cadence.

The reason why Cadence overpowered Chrysalis and the changelings is because Shining Armor was there. Cadence's main magical ability is power over love, as far as I can tell, and being with the man she loves attempting to save the Country that she loves must have supercharged those powers to an incredible level. She transferred her magical power (that was previously supercharged) to shining armor, so that he could create a spell that would create a new Force Field (or maybe "force Push" would be a more appropriate term) that would expunge the Changelings from Equestria.

So, technically speaking, Shining Armor, captain of the Royal guard, AND cadence, who just happens to be an alicorn, were the ones to defeat Chrysalis. Those two combined would probably overpower Celestia, but Cadence alone vs. Celestia would probably come down to Celestia winning.

Like a changeling, Cadence's power source is love. If there's no love to gain power from, then she has no power.

Well, duh! I agree COMPLETELY with btflash. Twilight's magic is nothing compared to Celestia's