Wolf Lord
4 attacks. With
Counter-Attack.
Belts of Russ aren't free.
Beastslayer, Majesty, Wolfkin, Warrior Born, Bear
Rune Priest
Rune Weapons turn Daemons to crap. The Avatar doesn't even have Eternal Warrior. Force Weapon time! Rune Weapons are also like Psychic Hoods, but slightly worse.
Chooser of the Slain: Put it somewhere awesome so enemy Infiltrators can't take that spot (like an objective), and/or put it somewhere where it can see everything.
Beastslayer, Warrior Born
Thunderclap: Nothing to write home about.
Living Lighting: Tell your friends! Add Saga of the Beastslayer.
Storm Caller: Meh. You don't really need it.
Tempest's Wrath: It's almost like Rune Priests hate Chaos Daemons...
Fury of the Wolf Spirits: Meh.
Muderous Hurricane: Screws over your opponent whether you cause casualties or not.
Jaws of the World Wolf: Not really that good. Screws over gun 'lines' if you get the right angle and Carnifii. Not too much else. Doesn't even work on Walkers or Vehicles.
...All the good ones are Shooting attacks, so you can only use one per turn. Living Lightning and Murderous Hurricane are the favourites.
Wolf Priests
Like a Chaplain. Except gives
Preferred Enemy against a single unit type ('Infantry' will still hit roughly 85% of everything in the game). However, note that a Chaplain's ability only works on the turn that they Assault. Wheras Preferred Enemy works
all the time. And Space Wolves have Counter-Attack on a Wolf Priest's Leadership 10? Who needs to initiate Assault?

Not Space Wolves.
Beastslayer, Hunter, Wolfkin, Warrior Born
Wolf Guard Battle Leader
Like a Wolf Lord, but cheaper. And still has an awesome stat-line. WS5 and 3 Attacks.

Only difference for wargear is no access to a Belt of Russ and different Sagas.
Beastslayer, Hunter, Wolfkin, Warrior Born
Wolf Guard Pack
Not as good as Sternguard. But, also only 18 points each. 2 Attacks each plus Counter-Attack. As the 'Veteran' unit, they can take pretty much any weapon they want.
Also, a cheap source of Terminators;
Power Weapon and Storm Bolter = 33 Points
Wolf Claw and Storm Bolter = 38 Points

Power Fist and Storm Bolter = 43 Points. Meh. You're paying the same points as Dark Angels and a smart Black Templar player. You've still got Counter-Attack.

Dual Wolf Claws = 48 Points.
Thunder Hammer and Storm Shield = 63 Points. Each.
This author has seen Power Fist and/or Wolf Claw and Storm Shield combos used to great effect. Assault Cannon and Storm Shield can be mean.
Space Wolves also don't have squad sergeants like just about every other army. Instead, Wolf Guard actually get 'split off' from the main pack to join other Packs as Sergeants. It's a fairly neat rule. Except, you still need a minimum of 3 Wolf Guard even if you just want one to use as a Sergeant.
Dreadnought
Assault Cannon as the base weapon.

Can take funky Space Wolf gear.
Venerable Dreadnought
Assault Cannon as the base weapon.

Can take funky Space Wolf gear. Including
Majesty so you can take the better Sagas on your Wolf Lord.
No Ironclads.
Iron Priest
Free Thunder Hammer.
Wolf Scouts
Space Wolf Scouts are actually Elites (just like in the real world) and have the Stat-line to match. Wolf Scouts also have access to Assault weapons like the Meltagun or Plasmagun. As well as also have a really cool rule which allows them to come onto the board from your
opponent's table edge.
Sniper Rifles cost points.
Lone Wolf
Has both
Bear and
Beastslayer Sagas (but he doesn't really, so your HQs can still have them). Which is exactly what you want. Strap on Terminator Armour and a Storm Shield and he wont die anytime soon. Problem is that he's
not an Independent Character, and using a whole Elites slot for just one model just isn't the best idea.
He's also missing access to a Jump Pack, Bike or Thunderwolf Mount. Which would be really handy.
Grey Hunters 
Like a Tactical Squad, but can't take Heavy weapons. But can take dual Assault weapons instead. And, even though they don't have access to a Sergeant, they can still have a Power Fist/Weapon anyway. And then a
separate character with the Mark of the Wulfen, and then add in another Wolf Guard. Oh, and Grey Hunters also have Combat Weapons and Pistols for another attack. And Counter-Attack.
Grey Hunters also have access to Wolf Standards. Take it or leave it.
Because of the fact that Grey Hunters can't take Heavy weapons, and the fact that they have Counter-Attack as well, they make ideal Drop Pod units.
Problem; Space Wolf Drop Pods only carry 10 models. It means you can take 10 GHs and get the two special weapons (Flamers or Meltaguns usually)...Or take 9, and the Wolf Guard, and only one special weapon because you don't have 10 models...Just keep in mind that Wolf Guard get Power Weapons and Fists for cheaper than Grey Hunters (but not really, because you lose the free second Assault weapon)...It all depends on what you want.
Blood Claws
Blood Claws
can't shoot at all if they're within 6" of an enemy unit, and then, they must Assault that unit. Clever opponents will put a Land Raider in front of them.
Blood Claws can come in squads of up to 15. But, you should also know that putting a Wolf Guard in the squad means they can shoot and not-Assault like normal people.
...Blood Claws are not a Defensive unit. They're
much better on the Assault rather than Counter-Attacking. Stick them in a Land Raider to near-guarantee to get them where you want them to be.
Thunderwolf Cavalry 
The best unit in the List. 12" Assault Move. S/T 5 and two Wounds each and all 5 of their Attacks are
Rending. Strap on a Storm Shield and watch them win. Who cares if they're 80 Points per model. They will win.
Trouble is, there is no easy way to make them. Best and easiest way is to buy multiple Canis Wolfborn models and go crazy with a saw. This is crazily expensive. But, it seriously is the best unit in the Army.
Swiftclaw Biker Pack
Like Blood Claws, but on Bikes for
Relentless Twin-Linked Bolters and T4(5). Bikes they'll be able to Assault what they want to Assault. Or get a Wolf Guard.
Cheap Attack Bikes.
Skyclaw Assault Pack
Like Blood Claws, but with Jump Packs. Add Wolf Guard.
Fenrisian Wolves
Wolves. On the Battlefield. They have the statline of a Space Marine, except with 2 Attacks each and terrible Leadership and save. Still, they're really cheap and have 12" Assault move.
Long Fangs
Due to the fact that no other squad can take Heavy Weapons, these guys can take
five of them. And then, split their fire between two targets
at the same time. The unit gets expensive if you're not careful.
Land Raider
Only carries 10 models.
No Thunderfire Cannons.
Drop Pod
Only carries 10 models. No Locator Beacons.
Bjorn the Fell-Handed
A Special Character Dreadnought.

He has a 5+ Invulnerable. On a vehicle...Very overpoints'd though.

If he dies, he counts as another objective. This can be used to turn a losing game into a draw.
Ulrik the Slayer
He's pretty good.
Arjac Rockfist - Wolf Guard upgrade
He's a beast. Almost as good as Lysander, except without enough wounds.
A tad overpriced.
Lukas the Trickster - Blood Claw upgrade
LOLOLOLOLOLOLOLOLOLOLOLOLOLOLOLOLOLOLOLOLOL!!!!1!! !111!!!!11!!
That is all.
Njal Stormcaller
Canis Wolfborn
Kills Infantry dead. Sadly, he has no Invulnerable and no Eternal Warrior. Stay away from pie plates.
Ragnar Blackmane
He's quite good.
Logan Grimnar
He's a pretty funky dude. And turns your Wolf Guard into Troops. Some people have been using him to field Terminator armies because Space Wolves get cheaper Terminators. Pfft. Logan Grimnar costs a truckload more than Belial. You need to take at
least 21 non-upgraded (

) Wolf Guard Terminators just to break even. Non-upgraded.