Versus Necrons

I am probably going to be getting into a game here fairly soon with a buddy who has just started collecting Necrons, I have NEVER played against Necrons at all. What should I consider taking at 600 points to be somewhat challenging, but not overwhelmingly so?

I have Tons of Kabalites, 15 Wyches, 1 Razorwing/Voidraven, 2 Ravagers, Lelith, 1 Haemonculus, 1 Archon,1 Sliscus 4 Raiders, 2 Venoms, and I could potentially ally with a few GK (Inquisitor Coteaz+3 Warrior Acolytes+Vect is hilarious...you get a 4+ rerollable seize initiative for 112 points of allies).

Any suggestions are welcome.

Against Necrons, Venoms, Kabalites in Raiders (all with night shield) are pretty good. Without knowing what kind of list he fields, I cannot be more specific.