Well, are they going to exist in the Far Lands? Probably not. It would take a while to pay them a "visit".
I say keep the name as Enderman and keep the name Far Lands.
Oh yeah. From the description that Notch posted a couple of weeks ago I always thought that Endermen would be like the "creators" of the Minecraft world. So that if they "created" it they could also "end" it. I like the skin for the Enderman because it looks like bedrock. And most of us know at one time bedrock was called admin rock or something like that... And who creates servers? Admins!
i much prefer the name enderman to farlander.
farlander sounds more like a human, that is from the far lands (like a highlander or something).
enderman sounds like a humanoid creature, which is what it actually is and so is more suited to this mob.
plus the community is already calling them endermen and if you suddenly change their name to farlanders, people will still call them endermen anyway.