The slightly more comprehensive answer to how much hit rating you want as a DPS warrior is 263 at level 80. This will equate to 8% chance to hit with special attacks, and assumes you have no talents that increase your chance to hit. Full Precision, for instance, provides 3% to hit, but it also costs at least 3 points to max and you have to have at least 20 points in fury to get it, so you're not likely to have it maxed if you have the 51 point talent in either arms or protection, meaning that for this discussion we can assume arms warriors won't have it. (Note: the current data seems to be that we need 8% hit against raid bosses. Previously it was thought to be 9%. I am using the 8% value here.)
Hit differs for Arms and Fury in that Fury simple cannot afford to try and gear for total miss removal on white attacks. The miss chance for a dual wielding warrior on white attacks is roughly 27% (assuming a level 80 warrior with maxed weapon skill against a skull level, functionally level 83 mob). So for a fury warrior, it's sufficient to aim for complete miss removal on special attacks, because in order to totally remove the dual wield miss penalty you would need over 800 hit rating. It's possibly achieveable but the sheer amount of hit you would need to shoot for would completely gut your attack power, critical strike rating, and other beneficial stats. You would be hitting with every auto attack but doing effectively no damage.
As fury, I don't take precision because at this point my gear has all the hit I need. It's worth keeping in mind that until you hit the point where your gear has this kind of hit rating, precision is a heck of a talent. With it, you will only need roughly 165 hit rating to be sure of not missing with a special attack. For an arms warrior, there's no precision bonus but arms also doesn't have the 27% chance to miss with regular, or white, attacks. (So named because the damage they do is reported in white numbers rather than the yellow numbers of special attacks.) What this means is that while an arms warrior will not have precision to help with specials and must aim for the 263 hit rating that equates to 8% hit against a level 83 mob, it also means that at 263 hit rating you will effectively never miss a special or a regular attack against a level 83 mob unless there is a debuff that lowers your chance to hit.
As the game currently stands, you can hit this target fairly easily for either arms or fury. My tauren warrior has the Cast Iron Shackles, Berserker's Sabatons and Gauntelts of the Culling from the moment he hit 80, meaning that he has over 100 hit rating from those three items alone. Various enchants for weapons and gear make hit a stat you can reach the 'soft cap' on fairly easily for fury and for which arms can achieve all it needs in level 80 blues.
Please, though, don't stack hit to the exclusion of all else. If you have 263 hit rating as an 80 arms warrior that's good, but if you achieved it by stacking hit to the point where you have less than 2k AP and 18% crit, you've done something wrong somewhere. Keep in mind also, the 8% (or 8.2% as some are reporting) number is against raid bosses, that is, functional level 83 mobs. The mobs in Heroics and regular level 80 5 man dungeons are at most level 82. This means you need less hit rating for them - your chance to miss a level 82 mob at level 80 with maxed weapon skill is 5.4%, meaning you need slightly above 177 hit rating without precision or 78 hit rating with it to be all good on hit for heroics.
Expertise is of two fold use for tanking warriors, as we covered last time.
You, however, are not a tank. (Well, you might be for all I know, but this is a discussion for DPS warriors. We covered you guys last time.)
You should not be in front of the mob. If you are in front of the mob, you're doing something horribly, horribly wrong. You should be behind or to the side of the mob, with behind being better because it's safer in a game where the mob is often not quite where we think it is due to lag.
If you are behind the mob, it cannot parry you, it can only dodge you. (You may see some parries if the mob is the type to turn to cast some spell or another, but those are unavoidable and we will ignore them.) Therefore, for a DPS warrior, expertise is only of value for removing the chance the boss will dodge you. Up until that point, expertise is as valuable, if not more valuable, than hit or other DPS stats. Once you have removed the chance for the bosses you're killing to dodge you, you do not need a single point more of expertise. This isn't like being a fury warrior dealing with hit, where a few points of hit over the cap for specials will just reduce the chance your white attacks will miss by a small amount. (This doesn't mean you should be stacking hit endlessly, either.) Also, unlike arms vs fury, neither DPS spec differs in how much expertise it needs, save for the presence of the Weapon Mastery talent in fury which reduces your chance to be dodged by 2%. (Weapon Mastery does not add expertise, which would also affect parries, it simply reduces your chance to be dodged outright. For purposes of DPS gearing the effect is the same, but the distinction is important to remember.)
Since the last time I wrote about expertise I've been swayed to the opinion that level 83 mobs have a 6.5% chance to dodge. Therefore, you need 26 expertise (which is 214 expertise rating) to remove dodges and once that is achieved, you're done. If you have that much expertise, you can respec and stop taking weapon mastery entirely, as you will gain no benefit from its 2% dodge reduction. If you have Weapon Mastery, you only need 148.42 expertise rating or 18 expertise. For a rule of thumb, remember that each point of expertise reduces your chance to be dodged or parried by .25%, and that it takes 32.79 expertise rating for each 1% dodge or parry you're trying to remove.
Finding DPS gear with expertise is not easy before raiding, but once you get into 10 man raiding the warrior DPS tier gear will have all of it you need. You'll drop weapon mastery so fast it will make your head spin.
Okay, this wraps up Hit and Expertise for warriors. Next week, we'll talk about PvP.