Till now (from the sticky unnofficial FAQ) four were stated: the Templar, the "knight" one (don't feel like looking up the proper name), the Sorcerer and the Warden (defensive caster). Taking into account that they will have to put a ranger (archer type) sort of class and maybe a rogueish one, that doesn't ammount to too many.
Since they didn't go for the no class feel of skyrim, I would like to see something the Oblivion classes (a whole bunch of them!!!), but this is an MMO and I'm afraid history will repeat itself and we'll have just a few options. I know any class will use any weapon and stealth (hence maybe the ranger and rogue types are really not needed...) and that there will be a possibility for every class to play some sort of trinity role (not sure on this and how the knight or a sorc will be a healer beats me though, from the descriptions i've found).
So bottom line, I always play support classes for the ease they have in assuming different roles (best option for that seems to be the templar), but would love that that same versatility could be found in all classes.. OR just give me a bunch of different classes so there are so many available that no particular one is essential.
What do you guys thin about this?