I initially leveled as a GLD when ARR first came out, patch 2.0. I went STR all the way while leveling, and it was the best decision I ever made. Where as every other tank seemed to have trouble keeping aggro, I had no problems. I didn't even have a problem after level 30 but before level 40, where most GLD/PLD suffer from DPS classes getting their AoE skills.

Until level 40 as a PLD, when you get Shield Oath, or level 30 as a WAR, when you get Defiance, both of which are enmity-increasing tank-buffs, you should definitely throw all attribute points into STR or you will suffer lots of lost aggro. After that, it's more situational, but I always felt that STR > VIT unless you needed the extra VIT for a mechanic or something.