[Striiker]

The ZEM's are incorrect. A developer was laughing at the list a while back on IRC. He was commenting that the numbers are way of (as others have pointed out) . I think at best, use it as a guide when looking for zones which may give better XP than others.

As for grouping, I'd advise avoiding Oasis and LOIO as well as they can be pretty dull. I guess you can give them a shot and see just how "exciting" life is in these zones. I also advise looking to do dungeons such as Unrest (one of my favorite zones), SolA (crazy XP modifier, Upper Guk (great XP as well), etc.
There are some good zones in Kunark as well at the lower levels but you may need to bring your own group..