At level 80, 32.79 hit rating reduces your chance to miss by 1%.
Thus if you are a Level 80 character with a Weapon Skill of 400, you need a Hit Rating of 263 (8.00%) to never miss a shot against a Level 83 boss (or skull mob) with a special attack or single-wield auto-attack. What this means is that there is a big +hit benefit to keeping your Weapon Skill within 10 levels of the mobs you are trying to fight. For example, by improving your Weapon Skill from 390 to 395, you effectively reduce your chance to miss against Level 81 mobs by 3%! However, after getting to 395, increasing your Weapon Skill the next 5 levels, to 400, only reduces your chance to miss by an additional 0.5% (or 3.5% in total).