Getting to 60 is just the start of the game. In fact, there are quite a few different levels after 60, based on what level gear you possess. This will all become a moot point once TBC (The Burning Crusade expansion pack) arrives and the level cap is raised to 70, but currently 60s are roughly divided into the following (made up) categories:
- Noobies (aka noobs, nubs, n00bs). Fresh 60s, wearing mostly high level greens and blues.
- Bluebies. People who have been 60 for a while and have collected most of the blue items for their class from low level instances (e.g. Strath, Scholo, DM, BRS).
- MCers. 60s who have been farming MC-level content for tier 1 epics (or equivalents), mostly from MC (Molten Core), ZG (Zul'Gurub), and AQ20 (Ahn'Qiraj 20-man). Note that a lot of blue gear from ZG and AQ20 equals or exceeds MC tier 1 gear, thus people in this category are often confused and lumped in with Bluebies.
- T2 (aka Tier 2). These people have graduated from the lower raids and have replaced most of their MC gear with BWL (Blackwing Lair) Tier 2 epics. Players at this stage are generally "epicced out" (i.e. most items are epic quality)
- T2+. Comprised of those who have mostly all Tier 2 as well as AQ40 upgrades. This is essentially a sub-category of T2, as these players are just slightly better geared than their T2 counterparts.
- 1337sauce. Probably less than 1% of 60s fall into this category. People who have been 60 for a long time and have gone through all of the previous categories, and have joined serious raiding guilds. These players have all of the best epics from BWL and AQ40, and are now upgrading those pieces with Tier 3 and other Naxx (Naxxramas) epics.
Something to note... the last patch essentially removed the "Bluebie" category with the new PvP system. Now fresh 60s are just a day or two away from getting PvP epics (including weapons) that are roughly equivalent to Tier 2/BWL gear.
Also... don't be discouraged if you are a fresh 60 (i.e. noob), and everyone you see far outclasses you gear-wise. The new level 60-63 quest rewards and dungeon drops in the expansion will allow you to catch up to those that are currently in the "MC" category, and by level 65-67 you will have caught up to the T2/T2+s. Once you hit level 70, all bets are off and everyone will be (more or less) equally geared, as the quest rewards and drops from level 68-70 match or beat Tier 3 quality epics, without having to do 40-man raids.