Gearing up to Tank the Bigs

All right, so I've managed to meet the minimums, and I'm slowly accumulating better gear.  Eventually I'm going to want to be able to MT Heroic raids instead of just occasional 10 mans.  

So what do I want to shoot for?

Originally I had this sneaking suspicion that I wanted to be aiming for def, hit, and expertise (soft) caps, and let everything else fall where it may.  Now, though, I'm not so sure.  I think that with judicious use of your vigilance and other abilities, as long as you have "some" hit adjustment, it may not be necessary to have full hit cap.

My original idea for gear to accomplish this was here:

All three caps on gear

Now the only reason I'm not "married" to this idea, is that it involves an awful lot of precision and doesn't leave much room for flexibility.

But I'm beginning to wonder if maybe losing a "small" amount of hit rating in favor of some extra expertise might be nice, especially if it could be done while adding some other mitigation as well.