necrons and their allies

[jgebi]

I am looking at having a secound army and with the allies chart I want it to work with my necrons. So I have to wonder which army out of choas space marines, grey knights, orks and tau.

I'm looking for one to plug the gaps and most importantly has good lore so who elas would I ask but the good chaps on BoLS so your takes?

[Learn2Eel]

In no particular order...

Chaos Space Marines - Not sure on how "fluffy" this is, but no doubt this opens up room for a very cool themed Thousand Sons/Egyptian army. Rules-wise, use Chaos Space Marines for fast assault units - such as Maulerfiends and Juggernaught-mounted Chaos Lords - and maybe even a Heldrake or two.

Grey Knights - You could do a cool radical inquisitor army, though if you mix the two armies you can expect quite a few people to label your army as cheese for no truly justified reason. Actual Grey Knights or a Henchmen army are both good choices here; they will add a lot of firepower. Plus, who doesn't want a Stormraven or Dreadknight?

Orks - As long as you don't mix Imotekh with them, why not? Though the Orks are the spawn of the Old Ones, they are either mercenaries or easily manipulated; the latter of which Necrons excel at. Trukk-mounted Boyz and Nob Bikerz would be the popular choices, and give your army some incredible melee punch.

Tau - Being Tau, they don't really care who you are - except Orks, of course. As such, this alliance would be fine thematically. Rules-wise, go for your life; Necrons tend not to have much that ignores cover or deals particularly well with 'hordes', so a Riptide and maybe a Hammerhead with an Ion Cannon paired with either Pathfinders or Marker Drones would be pretty groovy.

I'm tired and incoherent, so that is the best I can do for now.

[jgebi]

that gives me a starting piont now to jump in

[Sly]

You could use Dark Mechanicus-style miniatures for the Necron contingent of a CSM/Necrons force.
Statistically, CSM are the best matchup with Necrons, because the two things that Necrons lack are exactly what CSM is best at: AP3 weapons and killing hordes.

[jgebi]

my army dose alright at smashing hordes for some reason and I've got enough anti space marine power as is, looking at grey knights for a rapid strike up their *** to lock down some of their units