So my local GW Store is holding its first mini tournament. The challenge is to build and paint a 600 pt force in just 6 weeks and then take part in a tournament on a scenery heavy 4' x 4' urban board against any other forces that manage to qualify. I'm not actually taking part, but a friend of mine is and plans on a Dark Angels force which I've been helping him refine his army list. It's a fun challenge to try and come up with a list in that tight an amount of points that can conceivably take on any other force with a good chance of victory. This is what we've come up with thus far:

Dark Angels List - 600pt Challenge

HQ

Company Master - 90 points
Power Armour, Bolt Pistol, Chainsword, Iron Halo, Frag & Krak Grenades.

Troops

Tactical Squad I - 127 points
Sergeant with Chainsword & Bolt Pistol.
7x Marines with Plasma Cannon

Tactical Squad II - 127 points
Sergeant with Chainsword & Bolt Pistol.
7x Marines with Missile Launcher (Frag & Krak Missiles)

Heavy Support

Devastator Squad - 191 points
Sergeant with Signum, Auspex, Chainsword & Bolt Pistol.
8x Marines with 2x Lascannon, 2x Heavy Bolter.

Whirlwind - 65 points

Total = 600 points

I think it has plenty of firepower with a good range of Str/AP to take on varying targets. The Whirlwind allows the force to deny a cover save to a target unit, the auspex allows the Dev Squad sarge to reduce an opposing units cover save. The Dev squad is combat squadded with the sarge joining whichever half needs him most depending on the army being fought.