My GK army lists

One thing's for damn sure:  No more dual Land Raider crap if you want to play competitive.  Believe it or not, I've never played dual LRs for pure GKs.  I don't believe in taking 250+ point transports when most of the army is already so damn expensive.  Maybe because I like playing with a lot of Grey Knight Terminators and thus I spent most of my time DS'ing or footslogging.  You know what, I'm doing it again for this upcoming codex.  Now that the rest of my troops can take Rhinos, they're going to be the ones taking objectives and getting things done.

Check out my army lists:

2000

HQ:
Mordrack = 200
+10x Ghost Knights (Halberds, 2x Psycannon, 3x Warding) = 430
Lv.2 Librarian (Warding, +3x Powers) = 200

TROOP:
10x GKSS (Rhino, 2x Psycannons) = 260
10x GKSS (Rhino, 2x Psycannons) = 260
5x GKSS (Rhino, Psycannon) = 160
10x Terminators (Halberds, 2x Psycannons, 2x Warding) = 490

In this first list, you'll see my love of Grey Knight Terminators play out with purpose.  GM Mordrack enters battle on turn 1 with his retinue of Ghost Knights and start pouring down the fire.  They will find a good place to take cover from and lay down suppressing fire and will cast Psychic Communion so reinforcements can arrive.  Depending on the mission, Mordrack's Grand Strategy will either give the Librarian's Terminator unit Scout or re-roll 1s if I want things deader.  Scout allows me to outflank with +1 to reserves from PC, and I can always DS straight in another strategic location if I wanted to.  The Lv.2 Librarian has +3x powers which will probably be Quicksilver, Might of Titan and Summoning.  Quicksilver allows Grey Knights to fight glass hammer CC like Harlequins and triumph, Might of Titan punches through armor with ease and Summoning can bring squads to reinforce the front lines or bail Mordrack's squad of dudes out of trouble.

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2000

HQ:
Lv.2 Librarian (Warding, +3x Powers) = 200
Castellan Crowe = 150

TROOP:
10x GKSS (Rhino, 2x Psycannons) = 260
10x Purifier (Rhino, Halberds, 2x Psycannons) = 315
10x Purifier (Rhino, Halberds, 2x Psycannons) = 315
10x Terminators (Halberds, 2x Psycannons, Warding) = 470

HEAVY:
5x Purgation (Razorback, 4x Incinerators) = 145
5x Purgation (Razorback, 4x Incinerators) = 145

This next list focuses more on Purifiers and how awesome they are.  The extra attack and Cleansing Flame makes fighting horde units exceptionally awesome.  The Librarian has +3x powers again and he'll hang out with the Terminator squad with Crowe.  I'm not sure whether I like Halberds or Hammers yet but I'm sure that Quicksilver makes Halberds rather obsolete.  We'll see though.. since there's plenty of stuff that's still a mystery (like all the wargear options).  The rest of the units is pretty self explanatory.  My Purifier loadout features Halberds because the extra +I will allow me to engage MEQ without fear.  The GKSS unit is also pretty standard with 2x Psycannons and the Rhinos are there to keep my precious GKs safe from harm.  Depending on what kind of scenario the game is, I'll either sit back and shoot with my Psycannons or engage in a full out assault because my 2 Incinerator-totting Purgation squads are begging for some action.  This list is best used with the Librarian's unit footslogging and laying down firing support (plus drawing fire) or coming in via DS while the rest of the army surges forward.

I spent the better half of 4th Ed. footslogging my Grey Knights into their deaths by Nidzilla, Tau Suit spam, Dual Lash and other power lists.  As much as I'd like to get revenge for all those brave battle-brothers lost, I'm more or less disappointed with the new book.  It might be the old school GK player in me, but I don't think the new book captures the essence of Grey Knights at all.  I'm pretty sure it's a Mat Ward book because the fluff is outrageous, there's a serious overdoing of psychic and I have no idea why all 3 branches of the Inquisition is in a GK codex.  For some reason, I feel like I'm playing Thousand Sons minus the PE: Daemons.