I'll comment on a couple of these:
I have a 10K Chaos Army (7K of it is actually painted) and a 10K O+G Army (8K of that is painted but I've got a brigade of Trolls and a Brigade of Black Orcs - Bel style with pig faced helms! - on the go as we speak!)
Chaos - You need to think in terms of brigades, is it a "hammer" brigade (e.g. knights, chariots,Dragon Ogres) or is it an "anvil" brigade (e.g. warriors, trolls, ogres, spawn) or is it a cheap, add to the break point brigade (e.g. marauders, hounds). I always try to field a ratio of 1/1/1. Too few hammer brigades and you wont be able to smash their cavalry, too few anvil brigades and you wont be able to take/hold terrain or a line of battle, too few cheap brigades and you'll be so outnumbered and have such a low break point that it will be difficult to win.
O+G - Night goblins are pants, absolutely pants. I take the minimums to lurk at the back, boost the break point and protect the artillery from flyers. Other than that, just hide them at the back. Take LOTS of Orcs, Boar Boyz, Ogres and Trolls and Black Orcs. The danger of playing an all goblin army is that you will enjoy collecting it, enjoy setting it up but then not have much fun as you are mashed in every game you play. In my 10K O+G list I have 20 Orcs, 8 Black Orcs, 4 Ogres, 4 Trolls and 12 Boar Boys - these are what will do all the killing. Also take lots of heros!!! e.g. You will need 12 Orc heros just to lead this part of your army, never mind all the rest of the "tat."
Dave
