This is my Day 4 post in Spellbound's 20 Days of WoW Blogging challenge.
Here's the answer that was brought home when my Mage was giving Orphans tours:
Rune of Teleportation
I keep a stack of both these and Rune of Portals in my bags at all times now. I'm happy to make a few gold answering those "lf port to Dal" postings, but I love the freedom of bouncing all over Azeroth myself with quick and simple ports. I finished my Children's Week touring (except for Hail the King, yay, and Hard Knocks, grrr) in minutes. The experience was so painless I couldn't bring myself to run those quests on any of my other alts!
Is that your final answer?
It is. I feel naked without a stack of runes in my bag. Seeing them in there is more satisfying than any other item I've owned.