So far we know that chanters will be sorta like bards. The issue is, bards are a little bit of everything, and really just plain sucked until third edition, and then just mostly sucked until Pathfinder (Where they got their masterpieces, like being able to mime a 10 foot by 10 foot wall in less than a turn). I personally though, despite the massive suckage that they had, loved me my bards. I don't know why, but the idea of singing or dancing my way into combat, and making terrible puns while I bash people upside the head with my Axe (Bass) just really appealed to me, so I plan on Chanting it up for my first character.
I'm personally thinking that the Chanters are probably just going to go the way of dedicated passive buffers. Maybe something like Song of Hero's, courage, and skills, but with more versatility. Maybe throw in a Fascinate as well, and you've got your standard Buffer/Mesmer archtype.
Where do you guys think they're going to go with the Chanter?