Cool Tools (web based tools for gear)
I used these tools back in the day when all I played was my warlock and hunter, but it looks good to use for tanks as well... it ranks your gear/enchants and tells you were u can get upgrades and what instances you would be ok to go in.
just choose your area (US, EU, or whatever) your server and your toons name, you can also do an assesment of your guild(lvl 80's only)
It may or may not work right now with the servers being down...but it will give you some pretty good ideas of what to expect with your current gear.
Sorry if this is a repost or you already know about it.