I have every gathering profession on each of my groups. It is just too painful to walk passed a node and not be able to hit it. Passed 60 (well, actually passed RAF), levelling gathering professions is really easy. I never had to actually go "farming" at all. On my last group, for instance, I hit 375 minging (the most difficult, it seems) at level 67, just in time before heading north.

Gathering professions to me include enchanting. I want to be able to DE instance loot.

I also levelled a Tailor in my last group, for the extra cloth loot. I don't know whether it will prove a good deal, though, as I didn't have it on my first group to 80 (the only one passed 70 for now).

Bottom line is that I would not skip any of the gathering profession. I mostly don't have any crafting profession in double, though, so my groups have plenty of "profession slots" left. I like to fill them with herbing and mining (left at level 1) so I have the "radar" ability on several characters in the group.