I went VIT leveling and then switched over to STR for 50 stuff. Such a huge difference. I have two different gearsets and I swap based on pull and content. I can have defiance off and out threat other tanks. This is actually an issue. Run CT in full strength accessories/spec and laugh at any other tank who is trying to get the boss back.

The only reason I went VIT for leveling is because I didn't know any better and thought the HP was needed. It would be good to have both sets to make your healers job a tad easier when needed. Some healers will be fine but others won't. But for points just go STR.