I'd say hold off on the One X, if for no other reason than the One X+ is supposed to be announced on Wednesday. It's supposed to get a spec bump and a battery bump.
Also, if you're into rooting and using custom roms, make sure the bootloader is unlocked. Case in point, the AT&T version is rather locked down, but the Canadian LTE and international Tegra 3 versions are not.
Finally...how long are you planning on keeping the phone? If it's just for two years, the battery should be enough. If longer...find out if HTC will replace the battery for you once its capacity begins to degrade. Apple does this (though of course they charge an arm and a leg for it), but I haven't found any mention of HTC even offering the same service at any price.