Since hitting level 80 it's been an orgy of heroic instances. After 6 days and about 25 hours of /played at level 80 my discipline priest is now reasonably well geared, has done all the 5 mans, and has seen parts of ICC-10. 4/5 Tier 9 (ilvl 232) and an assortment of other epic niceties. The main upgrade I need now is a weapon. In one week at level 80 he's got better gear than Flyv, my feral druid main, earned in a year of play through Ulduar.
Partly I'm bragging, but mostly I take this as a sign of how hard Blizzard has worked to make endgame content available to new players. Flyp has never set foot in Naxxramas, Ulduar, or Trial of the Crusader. He's never met Sartharion or Malygos. It'd be pretty hard for him to find a group for those raids. Instead the gear comes from emblems from a bunch of heroic instance runs. The random dungeon finder tool works way better than I'd ever expected. It's fast, fun, and people are mostly polite. A sprinkling of PvP gear helps fill in the gaps and in a week I can gear up to where I can begin to hold my own in Icecrown Citadel, the premier raid.
It's pretty addictive to play as a new 80. Every instance seems to hold a loot upgrade, and just when you've seen all the ilvl 200 loot tables for the basic 5 mans you get to the patch 3.2 harder instances with ilvl 232 gear. Even if nothing drops, you've still got your emblems, at a rate of about 5 minutes / emblem. That's about 15 hours to pick up 4/5 of the entry level Tier 9. Playing a healer keeps it interesting, too, since every group has a different challenge. (In general healing the tank is the least of your worries.)
A note on GearScore. I'm an unabashed fan of the GearScore addon, which summarizes a player's gear with one single number that's essentially the average ilvl of their gear. It's a ridiculous, dehumanizing, reductive way to evaluate a player. It ignores skill, item synergy, and play style. It's also ruthlessly efficient and easy to understand. My only complaint is Blizzard isn't publishing their own internal calculation as a standard. Instead some people use the addon, some people use wow-heroes, and unfortunately the scores are on different scales. But it's nice to have a scale to measure myself and others against.