As early as Hellfire Peninsula (which I'm playing through on my Hunter right now), it becomes pretty clear that Blizzard packed Outland with quests and things to do. By the time you hit Zangarmarsh, you're probably already at 62, and with a few instance runs, it's pretty easy to get all the way to level 70 without ever seeing certain quest areas or zones in Outland. So Dacronic wants to know: what zones did you save for level 70, when you didn't need XP any more and just wanted to get money or have fun?
On my Shaman, I barely saw Netherstorm before 70, and went up there way after I'd hit the highest level to go looking around for cash. And there are lots of fun quests to do up there, too. Shadowmoon Valley was another one that I didn't actually quest in for a while after 70, but now that I've done it, I'd say that it should actually be a priority ASAP-- there are a ton of terrific quests in SMV, not only for lore's sake, but just really well-done content as well.
When you hit 70, what areas did you head towards to continue questing in? And what areas did you "save" until you were as powerful as you could get, and reading to have fun instead of just grinding?