good units against necrons?!?

the army i play against most often is necrons, what units are good against them?

Anything anti tank should be your first priority since crons can field tons of av13 without even really trying and most with jink. After that pretty much all our core units are worthwhile against them as long as you can deal with their mech aspect. If not its straight lose once they eliminate our AT.

From there it depends, I always see a strong mech element and then imotekh, FW tomb stalkers, teleporting spiders, wraithstars, plus other odd stuff. In most of these instances a huskblade can be pure gold.

NIght shields are also really really good here since their entire army barring lanceteks and imotekh is range 24" = 18" ranged army (im speaking of units they actually use although you run NS long enough you might even see doomsday cannons and hvy gauss cannons hit the field).

It depends on the Necron army.
I have two players in my group, the first plays vehicles and lots of warriors, the second plays more CC with wraiths.
Against the first kind of army I prefer to play a CC army - wyches and beasts with long range firepower from ravagers and raiders. Against the second army I play venoms with warriors. The poison spam will handle the wraiths with 2 wounds and and inv. save.

I've got to say that beast units have been really great in my games against Necrons.

The Razorwing Jetfighter's Monoscythe Missiles are amazing against scarabs.

Nightshields are pretty great against most necrons.

I already use night shields and they are an amazing upgrade