I like to use Warcrafter.
One example toon is my paly Soap

i'm not a big fan of the "you are here" raid graphs in be.imba or wow-heroes.. it's not like you're wondering where your next bit of gear will come from once you've reached Heroic Naxx.
I used to like be.Imba, but it's been too long since the class specs were broken and alot are 'still in progress'.

Warcrafter just gives you a plain hard gear levels, and for all toons of all guilds of all servers. it's nice to see where you stand and what other (higher toons) go for.
All the rest i just search on wowhead.

cheers,
-Zub