Here is some basic and useful information about the stats for raiding survival hunters. We're going to focus on information here that applies to level 70, 25-man raiding, survival specs for other purposes may benefit to some degree from this information but it may not all apply.
The key stats every survival hunter wants are agility, crit and enough hit to reach the hit cap but other stats are of value as well, the key is to make efficient use of the itemization available. Due to the way itemization works, the more of a stat is on a piece of gear, the more expensive it is itemization add more. Sockets do not suffer from this limitation so socketed gear will frequently give you the best bang for your itemization buck as survival.
   Agility is the most critical stat for survival hunter. 1/4 of your agility provides attack power bonuses to the raid via expose weakness whenever debuff is applied. This is the primary reason for the existence of the survival spec in high end raiding. In addition you will gain 26.5% bonus to all your agility in a raid, 15% from the lightning reflexes talent multiplied by the 10% from kings. So agility on gear scales very well with survival specs, it also provides dodge and armor on fights where those may be of use like Bloodboil.
We highly recommended that you do not switch to a survival spec until you have a minimum of 600 agility before speccing into it, which will net you roughly 700 agility with talents. More is obviously better and how much agility is required to make the spec work well depends on the level of raiding you're at. If you are too low on agility, you are better off staying beast mastery spec until you can assemble enough gear to make the survival work; otherwise you are likely to lose more DPS from switching specs than the raid gains from you being survival. There is very little gear that is good for a survival hunter that doesn't have some decent amount of agility on it.
Although agility is critical to a survival hunter, you still need to evaluate each piece of gear for the complete DPS benefit as well as the expose weakness benefit to the raid. Small amounts of agility gained for a loss of large amounts of lesser stats such as attack power will not benefit your raid as you will lose more damage than your raid will gain from your expose weakness contribution. For example, the 4 stats enchant to bracers is not as beneficial as 24 AP since you are only gaining 4 agility for a 24 AP loss. You'll note that most high end survival hunters don't usually get past the mid 900s because you'll reach a point in gear where your raid DPS will benefit more from taking lower agility items with higher other stats.
For a survival hunter, Crit rating is the second most important stat. You can get a fairly decent chunk of crit from having solid agility but gear that has good crit in addition to good agility is best. Ideally you want to get to at least 30% crit, but the more the better as your crit will affect how much of the time you can keep expose weakness up on a target in addition to the damage benefits. In addition your pet will gain more damage from your crit due to the go for the throat talent and if you have the thrill of the hunt talent you will gain more mana back as your crit improves.
If you are below the hit cap, hit is the best stat you can get to increase your personal damage output. For a survival hunter reaching the hit cap is fairly easy at lower levels of gear, but at the T6 level of gear hit becomes scarcer so you may have to work harder to reach the cap. The hit cap for a hunter is 9% but survival hunters get 3% hit from the surefooted talent, which you should pretty much always take unless for some reason you're way over the cap and have a better place to spend those points. So for the standard survival hunter you are looking for 95 hit rating to cap, if your talents differ that may vary.