Spend some time away from it all, in an exotic location where everything's new again -- make an alt. Preferably a cross-faction alt.
It sounds idyllic, in principle. Start life from scratch again, in a town where nobody knows your name. Learn new skills! Have fantastic adventures! Spend four hours killing wolves and only regain a fraction of your former power! (Eh?)
Alts are great, in principle. However, if you're like me -- and you have over thirty of them -- then even a journey away from your main becomes tedious and repetitive. I've seen every nook and cranny of every newbie area, through lenses as diverse as RP-PvP and plain ol' PvE. I've done every newbie quest a thousand times, or at least it feels that way. If I have to collect Bristleback Belts or deal with Iverron and his spiders one more time, I'll go bonkers.
I recently decided to start levelling a priest (it must be heatstroke; the British summer's just begun). "Great," thought I. "I'm always healing anyway -- this time I can be a healbot from the start, and learn to do it well."
I got to level 6 and quit. Not because I hated healing -- let's face it, at the lowest levels most classes are similar -- but because I couldn't face the thought of fifty-four more levels ahead, levels of endless running and grinding and repeating quests for ingrates.
But I know I'll be back. When the tedium of life in the fast lane gets me down -- when I decide to make "learn2heal" another pet project of mine -- or just when I've nothing better to do. Even if I never play this priest again, I know I'll create another, some day. I have a feeling the expansion will cure some of my newbie-area-phobia, but it's a sad fact that what was once exciting and new has become tired and old, despite the variety of newbie areas and the novelty of switching faction.