Well, I've just finished getting my first 3 BE mages to 60 (1 was gifted from lvl 41) and the following is how I went about it:

1-12 Starting Lands
12-26 Northern and Southern Barrens (I haven't done Ghostlands enough to know my way around and efficiently quest there, while I can group the Barrans quests really efficiently)
26-30 Stonetalon Mountains
30-34 STV
34-36 Thousand Needles, Shimmering Flats (the grinding and pick-up quests are worth the extra lavels they grant)
36-42 Dustwallow - now one of my favourite areas
42-42 Tanaris (Epic fail due to the hour spent getting ganked and reganked)
42-44 STV (BB quests)
44-48 The Hinterlands
48-52 Felwood / Winterspring (hit winterspring a bit too early, went back to finish the last 2 levels there)
52-56 Ungoro Crater
56-58 Silithus (MY GOD the scorpion/spider pickup quest has a lousy drop rate)
58-60 Winterspring

After some issues I had with my dual-box hunters, I will not do any Hillsbrad quests unless a) I run out of all other quests for my level (not an issue with RAF); and b) it is after 3am server time. The same now goes for Tanaris - it's just not worth it. In total I had 49 hours played, with about 3 of them corpse running.

STV is great as long as you do a lot of the questing at a dead server time, or the ally ganking can be pretty bad (this would depend on your server too, but my server has a 3:1 Horde to Alliance balance and there are still always alliance ganking there). There is also a lot of experience to be had in Felwood and Un'Goro with a little running around, though most of the Un'Goro quests are pickup ones (running dual- and tri-box, I'm not too bothered by pickup quests).

I'm having a break for a while before working on my last two mages, but does anyone have any suggestions about the best way to get from 60-70? (Or possibly even 80 by then, but let's not go there just yet) Will I be able to get much from 5 boxing mages in the instances, or should I stick with the zone quest options available to me?