Hmmm good question really
I wouldn't really know any other place than the desert areas. Newland would be quite the choice, it being neutral grounds, hence possible to put Omni and clan next to eachother. Of course it would mean that there would be lag hell erupting quite fast then.
I'd like to know something else as well by the way. Lately there have been drops in gas throughout the planet. Does this have to do with the coming of the peacekeepers or is it something that prepares for the boosterpack, making sure that existing areas that used to be 75% are now going to go down in suppression to 50% or 25% to make for PvP possibilities?
Okay, that last bit may be off-topic, but I wonder about it...
I would go for neutral grounds for the land-control, although I will get flamed for wanting to use the neutrals for clan and Omni pleasure ;-p