60: level up or gear up?

[Drommon]

Personally, I'd say quest. Do instances once you clear the zone and get the quests for the instances, then move on. Outland gear is going to be very quickly replaced by Northrend gear, and anything that is lacking at 80 can be made up with crafted gear.

Seconded^

Also when your team hits 80 you can unlock all those NR dailies that can net you a ton of gold.

Drommon