So with the release of the Scourge from Commorragh, I thought I'd come up with a list to deal with these fiends.
HQ Captain Tycho- 175
Elites Sternguard Veteran Squad (5)- 240- 5 x Combi-melta/Combi-Flamer; Razorback, TL Assault Cannon
Elites Sanguinary Priest (2)- 100
Elites Sanguinary Preist (2)- 155- Brother Corbulo
Troops Assault Squad (5)- 180-Melta-gun, Lightning Claw; Razorback, TL Assault Cannon
Troops Assault Squad (5)- 185-Flamer, Power Fist; Razorback, TL Assault Cannon
Troops Assault Squad (5)- 175-Flamer, Power Weapon; Razorback, TL Assault Cannon
Troops Assault Squad (5)- 180-Melta-gun, Power Weapon; Razorback, TL Assault Cannon
Fast Attack Baal Predator- 160-TL Assault Cannons, Heavy Bolters, Extra-Armour
Fast Attack Baal Predator- 160-TL Assault Cannons, Heavy Bolters, Extra-Armour
Fast Attack Baal Predator- 160-TL Assault Cannons, Heavy Bolters, Extra-Armour
Heavy Support Devastator Squad(5)- 130- 4 x ML
2000 Pts 4 Scoring Units 19 KPs
So basically, I threw around alot of S6 Rending Weapons to get by FNP, and they geared the BA up to have FNP themselves. I considered Tactical Marines, but that route had no power weapons in the army, and if Tactical Marines get assaulted, they will do worse than assault marines, and they would not have been shooting that much from inside the Razorbacks anyway.
You should be able to rip apart the Dark Eldar transports with ease, and the Assault cannons will tear through the Eldar themselves with ease. I leave it up to you to decide if meltas or flamers are better on the Sternguard. Flamers are sprinkled throughout to hit the bunched warriors once their transport is down. As well, one of the best ways around FNP is just to force alot of rolls, which flamers do. The Sternguard are there to give you some good revenge. 2+ poison weapons at AP5 will be annoying for your opponent, thinking he is the only one throwing around poison.
The devs are just icing on the cake. All ML allows them to krak raiders and frag clusters of guys, getting around FNP the same as Flamers.
The Baals are all set up for massed firepower, but you can switch to inferno cannons and flamer sponsons if you wish. The thing was the assault cannon can get tranports and infantry alike, and at range, where as the inferno cannon is really for infantry and has less range.
4 SPs, including Corbulo, to go in the Assault squads and make them resilient with FNP of their own, which will really help against Poison.