Triarch Stalker
Triarch Stalkers are giant metal spiders. They are traditionally used for flanking maneuvers and sideswipe attacks, but can do a surprising amount of damage when deployed on the front lines. They can wield a fusion laser cannon that can either be focused into a medium range cutting laser (the kind that is more effective at half range) or a wide, fanned out blast of boiling plasma. They also possess advanced targeting relays that can bolster any nearby Necron units' accuracy programming.
The Triarch Stalker is a walker with the Quantum Shielding rule. That means it is AV13/13/11. Neat. Also it carries the Necron's only melta weapon, which it can alt-fire as a heavy flamer. Double neat. Also also it makes every unit that fires on it's target twin-linked. WHAT. It can ignore Crew Shaken and Crew Stunned results and it has Move Through Cover. Double neat with chocolate sauce. It makes 3 attacks at S7 in close combat, and only the hidden power-fist (or equivalent) can really scare it. Super neat combo with fries and a drink. Its 150 points for a whole bucket of neat. and you can swap out it's Heavy 2 melta laser for a twin-linked Heavy Gauss Cannon (S9 AP2 36 inch Assault1) or one of the Necron's new guns; the Particle Shredder (S7 AP4 24 inch Large Blast).
A word of warning to this page, if you don't like complicated as fuck models, you will rage.