Thoughts on starting a new army

[Black Hydra]

Check out the specialist ranks and formations on this page: [url]http://warhammer40k.wikia.com/wiki/Emperor's_Children[/url]

Other than Possessed and Noise Marines, I'd say go with Cultists. In that section it has the Roaring Blades, infantry that supported the Emperor's Children during the Great Crusade. When they turned traitor so did the Blades.

Also Fulgrim has the Phoenix Guard, Terminator veterans basically. There is the Slaanesh Dread from FW, so I imagine they might use them.

Rhinos are a staple for any Marine force, be it Traitor or Loyalist. Maybe a Landraider. I'd use both Noise Marines and regular Chaos Marines, as both are part of the Emperor's Children. Noise Marines are just the guys who fell even deeper into depravity.

[Hunter]

in my humble opinion , it depends on you available disposable income and how much free time you have.

if there are models that are must have because there about to go opp , go for it .

can't go wrong with the basics such as rhinos and troops but stick to the basic load out , converted to your armies thematic ofcourse .
so in short , pick up a couple you know wont change and take your time to build and paint em