Rune Priests (part 2)

Right, now lets move onto equipment/wargear for Rune Priests.

Boltgun-for no points cost you can lose an attack and have a weapon that you are unlikely to use because you have better psychic powers.
Plasma pistol-ok, as a pistol this means that you get to keep your attack for 2 close combat weapons.  However, it nows means you have 2 things your model can do that will make it lose wounds.  Not worth it for 15 points, espically when so many psychic powers are used in the shooting phase.
Storm Bolter-very much like the standard boltgun.  Not worth it unless you have terminator armour.
Runic Armour-some people may prefer terminator armour over this, I like the fact that you can still ride with your Grey Hunter buddies in a rhino.  Even gives you a little extra psychic protection.  However, the lack of an invunerable save really does hurt this option.
Terminator Armour-not an option I would consider outside of a very terminator heavy army.  Does help make your Rune Priest harder to kill, but depends on how you build your army.
Combi weapons-again, why would you pay for options that detract from your ability to cast psychic powers. 
Jump pack-good with a bodyguard of Skyclaws, even if it is a pretty expensive option. 
Space Marine Bike-same as with the Jump pack, but a bodyguard of swiftclaws instead.
Melta bombs-a cheap way of meeting the requirements of 'the leaders of the pack' rule.  Some would argue that this isn't in the spirit of the game, but melta bombs do allow you to help out taking on vehicles.  These melta bombs have helped me a couple of times in games.
Wolftooth necklace-ok, you hit anything on a 3+ regardless of weapon skill.  This is an ok option, but only if you want to go character hunting in my opinion.  Most units that you have a chance against you will be hitting on a 3+ anyway, anything  that you won't hit on a 3+ naturally tends to go faster than you (howling banshees and genestealers for example).  The way I would use it is give it to the Rune Priest and go after independant characters with your Runic Weapon.
Wolf tail necklace-an extra save against psychic powers for 5 points.  Can't argue with that.
Chooser of the slain-a very useful item, giving your Rune Priest an extra ballistic skill if the target has a line of sight to it.  Can even be used to block infiltrators.  This can be exceptionally useful against some armies, I've had games in which I've forced infiltrators into a tiny space on their board edge.  The deployment denial aspect of the choosers can be useful, but it does depend on whether or not your opponent has infiltrators.
Master of Runes-if you have a spare 50 points floating around then I don't see why not.  Personally, I think there are better things to spend 50 points on in a Space Wolves army.
Saga of the beastslayer-not a bad saga if you know you will be facing certain units.  Chaos daemons and maybe tyranids spring to mind.  Otherwise, I think its a bit of a waste of points as the Rune Priest isn't the most combat effective of the possible characters.
Saga of the warrior born-if you arent giving this to either a Wolf Lord or Wolf Guard Battle Leader then its not worth giving it to a Rune Priest.

One thing to remember about Rune Priests is that they are great support characters, but they arent combat characters.  The fact that they only get an invunerable save from terminator armour really makes them fragile.

These Rune Priests are good for different lists, but again very situational.  Again, as always it does depend on your army list.  I am assuming for each of these options 1 Rune Priest in the army.

Terminator Runepriest in a drop pod/land raider
Obviously, you'll need terminator armour for this one.  As this Rune Priest is a bit closer to becoming a combat character, having a wolf tooth necklace is a good idea.  As you can survive against a lot more, being able to hit things up close a bit more easily can't hurt.  To be honest, its probably not worthwhile upgrading to master of runes because you won't be out of combat long enough to use that many psychic powers.

Mechanised list Rune Priest
Definately take a chooser of the slain.  Deploymeny denial when it works can be a fantastic thing and the extra ballistic skill against certain targets is always useful, espically if you are using living lightning.  A melta bomb is also good because you get that much closer to vehicles in order to destroy them.  The wolftooth necklace can work pretty well for this option, but it depends on whether or not you have the points to spare.

Footslogging Rune Priest
Like with the mechanised Rune Priest, a chooser of the Slain is always useful for all of the same reasons.  Runic Armour can be helpful in allowing your Rune Priest to survive more, but then again so can Terminator armour in a lot more ways.  Stormcaller is probably one of the best psychic powers you can take for this Rune Priest.

Rune Priest on a bike or with a Jump Pack
Pretty much the same as the footslogging Rune Priest, but without the Terminator Armour.  Melta bombs would help this build too, as the model will tend to be pretty quick.

Again, this isn't a complete and comprehensive guide.  This is just my own thoughts on the matter, but anything I can do to help others get a little better use out of their Rune Priests I would consider to be a good thing.