Those guys who get from say, 60-70 in two days seemingly is actually a guild effort. Here is how the procedure goes:
1. Serious guilds have a few people who enter the WoTLK beta
2. They study the beta and map out the most optimized plan for power-leveling.
3. Sit outside of the store at the witching hour and buy the game ASAP.
4. Organize time so that people play one character in shifts. I play for six hours, then my guildmate, then another guildmate.... That's 48 hours of solid power-level play without having to strain one person to lose sleep and concentration.
5. Organize a couple of body-guards to prevent cross-faction feuds which can slow things down, especially around times like launch dates.
realm first 70 (or 80 in this expansion) for prestige. Especially now with the achievements, its even something that stays. For us regular users it doesnt make a difference, though. Its even better to level "slower" to get to see the new content too.
Check out this video of a 5man group that decided to rush to 80 within 15hours.They got banned at 79 and accused of mob tagging(a game method of power leveling that they didnt fixed in tbc and in wotlk): http://www.worldofathene.com/ They explain the hole hardcore methode of it
I bought a game and cant log in for 2-3 days for now because there is a huge que of 1800 players on my realm "Ravencrest" eu pvp.