SOE has made the decision that Landmark, and probably by extension EQ: Next will be 64 bit games and they will not offer a 32 bit version. They now join Stardock as the first developers to develop 64 bit games only (Galactic Civ III will be 64 bit only as well, but they announced several months ago) This does not mean an end to the current 32 bit games, nor does it mean they will only develop 64 bit games in the future, but I think more and more software companies will be joining the 64 bit bandwagon in the future.
I think this is overdue to an extent, and may push system developers to start allowing more and more memory in their higher end systems as programs will no longer be limited to just under 4 gb of memory. This makes a bit of sense as the console systems have gone 64 bit already.