Okay, so here is the list i plan to be using on Sunday, (going up against IG, Nids, Orks and Smurfs). It is a bit weird but it's made up of models i already have (being a student with no money... :'(

(I blame union bars)

Anyway, tactics for this list
Seperate the two chaos icons into one cohort each, this guarantees me a landing spot for the rest of the list. The second herald is cheap but has a "suprise" up his sleave, if anyone gets too close by vomiting up a BoC. He stays with the PB's.

The Flamers i have found can deal with pretty much any unit if in range, but will have a tendancy to get shot up next turn so i plan to turn them on nobs, storm troopers, genestealers etc. Any elite infantry unit.

The PBs + Horrors go for the objectives and sit on them, they are both pretty tough units so once there the Horrors + Herald will see anyone near them off with Warpfire, and if the enemy get too close i can counter charge with the Plaguebearers.

Daemon Prince is expensive, but very much worth it and adds the kick to the army that it really needs, although he cant go toe to toe with a Hive Tyrant/Carnifex im hoping for him to carve his way through any tanks i come into contact with (very likely against the IG)

Ideally i would trade in the DP for another two units of Bloodletters or something, but, sadly, I do not have the models.

Any thoughts/advice?

Minor warp bleed- The horde of Eto'cara'tchen

H.Q.
Herald of Tzeentch
Master of Sorcery
Bolt of Tzeentch
Chaos Icon
We are legion
=120pts

Herald of Nurgle
Breath of Chaos
=80pts

Elites
3 Flamers of Tzeentch
=105pts

Troops
5 Horrors of Tzeetch
Bolt of Tzeentch
=90pts

9 Plaguebearers of Nurgle
Noxious Touch
Chaos Icon
=200pts

Heavy Support
Daemon Prince of Chaos
Daemonic Flight
Iron hide
Unholy might
Daemonic Gaze
=210pts

Mark of Nurgle on the DP is a must. T6 can (and does) make the difference...take unholy might and daemonic gaze, put the mark and noxious touch and he'll become a killing machine by itself. The rest looks nice.

Okay thanks a million, will do :D

5 Horrors feels a bit small, but then again, in 800..
I'd still cut a couple of plaguebearers to make more room, and perhaps the 'we are legion' from the Herald.

Then again, 'We are Legion' helps him some..

I would not necessarily expect to pull off the Breath of Chaos shot that the Nurgle Herald can fire off, but if he comes down in the second wave, he's got a good shot at doing it.

I think your big killer here would be the Nurgle-marked DP. It's pricey, but a flying T6 monster that hits on 3's and wounds on 2's without allowing armor saves WILL absolutely scythe through the enemy.