Grey Hunters (Part 1)

Grey Hunters are one of the most cost efficient troop choices in the game, with their special rules (counter attack espically) making them able to fulfil a number of battlefield roles.
One thing to remember with Grey Hunters is that they aren't elite combat troops.  Grey Hunters is a fairly standard space marine statline, it is the addition of their equipment and special rules that makes them better.  Remember, the more you have in a combat the more likely you are to kill your target.

Now, lets look at the equipment that our trust Grey Hunters can have.

Special Weapons
If you have 10 Grey Hunters in a squad, then special weapons are buy one get one free.  I would say this is definately a must for footslogging armies, there isn't a reason not to have large units with 2 special weapons that I can think of.  The hard part is when you start putting them into transport vehicles.  Some people swear by wolf guard pack leaders, some prefer having the full 10 men with 2 special weapons.  If you are new, try both whenever you can.  Find what works best for you.  Me, I tend to go for the wolf guard, but I will explain that at a later date.
Now onto the weapons.
Flamer: The age old arguement of quantity over quality.  Lets look at quantity.  Well, the flamer is free at all times for Grey Hunters.  This means more points to spend on other things in the army.  Secondly the flamer is able to hit and potentially wound more models than the meltagun or plasma gun.  The more dice you make your opponent roll the more likely they are to fail their saves.  The flamer is espically good against hordes, because they tend to have worse armour anyway and the flamer makes them lose any cover saves. 
Now, lets take a look at quality.  The strength of 4 is the lowest of the bunch, meaning it wounds marines on a 4+ rather than the 2+ the other two weapons do.  The AP5 means that marines get a save against it.  As a template weapon, the range is poor-so is probably best reserved for mechanised or drop podded units. 
Melta gun: My favourite option of the 3 special weapons.  Obviously the melta gun gun is incredibly good at hunting tanks.  Its also pretty cheap at 5 points.  One of the main advantages in my opinion is the fact that it is an assault weapon.  The fact that Grey Hunters seem to be happiest when charging means that the melta gun is perfect for them.  Also works surprisingly well against walkers and monstrous creatures.
Plasma gun: The plasma gun is the only one of the special weapons that is rapid fire.  Instantly that means that the Grey Hunters can't assault if they shoot with it.  Thats why I'm usually not convinced-but I am playing a mostly mech list.  However, in a unit in a drop pod this would work as they can't assault the first turn anyway.  Then, there is always the overheat special rule to consider.
Plasma pistol: Not a bad option, a little too expensive for my taste.  Plasma pistols are good against marines, though if you're shooting at low armour save models then its a bit of waste.  Does still mean you can assault though.
Power weapon: A good option, even though there are better.  The reasons for taking a power weapon for Grey Hunters are the same as for taking a power weapon for a marine sergeant.  Useful in small squads because you strike faster and more likely to get the hits in. 
Power fist: A power fist is probably a better option than a power weapon.  You do get less attacks than a power weapon, but your attacks are more likely to kill.  This is very helpful, as it means that you are more likely to win the combat.  However, you do strike last (obviously) so is more useful in larger squads because you are less likely to lose the power fist in the first round due to casualties.
Wolf Standard: Definately worthwhile in a larger unit that you plan to get into assaults.  The ability to reroll ones is very powerful.  The number of times they've helped me win combats means they are a permanent addition to my Grey Hunter packs.  However, I don't see much point in having this in a small pack (basically one in a razorback).  It works best with more models.
Mark of the Wulfen: Definately a good upgrade.  D6+1 attacks at standard with the rending special rule.  Yes please.  Mark of the wulfen is good in combat against most targets, but don't rely on it.  If I don't have points for mark of the wulfen and a power fist, I go for a power fist.  This is because other combat upgrades are more reliable and you can guarantee their results.  Mark of the Wulfen however is good and has the potential to do amazing things in combat.