There hasn't really been anything amazing out in the last 3-4 years, but in the next 6 months to a year, there's gonna be a couple MMOs that look like they might be worth a shit.
Warhammer
pros
existing fan base and name recognition guarantees a nice player base
supposed to have at least some focus on PVP
classes look cool
graphics look decent
cons
looks kinda like WOW, graphically and in terms of game mechanics
I want to play it the least out of the next gen MMOs because there doesn't seem to be much here that we haven't seen before
Age of Conan
pros
the screenshots I've seen so far look amazing
FPS-like combat, have to aim your swings, target your arrows/spells with a reticle, etc
it's set in a gritty environment full of pillaging and head chopping gore
cons
has some weird kind of leveling up system where it's single player until lvl 10-20
niche game that will only appeal to a limited player base
Pirates of the Burning Sea
pros
you can be a fucking pirate
you have your own fucking pirate ship
you can blow other asshole pirates out of the water and steal their booty
you can design your own pirate flags and ships and shit
cons
the plans for the PVP system change on a weekly basis
possible vaporware
Tabula Raza
pros
made by Lord British
has laser guns, pewpew
cons
made by Lord British
has laser guns, pewpew
Darkfall
pros
everything that would be kickass in an MMO
cons
not a real game