You want 5% to hit at least, unless you enjoy missing kicks and gouges. After that, you need a parse of your white/yellow damage ratio to figure out how valuable hit rating is for you in pvp.
Vs a stationary target I'm sure there's plenty of information available, but that's not really relevant in pvp, your playstyle is. If you consistently target hunters and mages for example, hit rating is going to be devalued, as you're going to have about 3 seconds facetime before you're being kited, raising your yellow attack ratio due to being able to throw out 80-120, maybe 140, energy worth of attacks and then being kited while energy recharges. 140 energy worth of yellows compared to 2-4 seconds of white attacks is going to skew your numbers heavily in favor of yellows, which only need 5% to hit.
So basically, aim for 5% hit rating as a bare minimum, including buffs like your elixir if you have it on regularly. After that, it's almost certainly more valuable to be picking up other stats.
The last thing I would add is that when working through the hit rating options for various brackets, you may find that despite the higher relative value of hit rating before hit cap, your dps will still suffer due to being forced to wear an inferior item in order to reach cap. At that point it becomes a matter of preference. I wouldn't suggest going below the 5% minimum to ensure your utility abilities don't miss, but some players may prefer to have that happen occasionally in order to maximize damage, and particularly burst damage. I think 19 rogues might be one of the classes that has this problem actually. I don't recall all of the gear options, but I know when you start looking at on level greens in slots that could be blue, and caster gear in other slots (with the exception of the spidersilk drape which is now pure awesome), things get a little blurry. If I recall right, 19 rogues are forced to look at those options to reach 5% without boa gear.