Well, around Serebii and most pokemon forums, the balance is tilting heavily to a Flying type, thought I still fail to see how Sylveon could ever be a Flying pokemon (unless it's some sort of play on the word Sylph and Eevee, with Sylph being usually a Wind sprite/spirit and Wind being associated with flying).

It could still be Light type, however this type would likely just fill the void between electric and fire. Although if you judge by this:

It definitely does look like a Normal type but I'm torn between Normal/Flying or a new type. It's been such a long time since any new type has been introduced Im almost starting to think those days are gone.

That image from GameFreak really does suggest it could be a flying type though (either that or its a big coincidence)... OK I'm going to guess flying :/

X/Y news coming Saturday! Hope some new pokemon show up