Warriors are your friends. The book is called Warriors of Chaos for a reason.
As a long-time Warriors of Chaos player, I've found over the years that a lot of the shiny stuff that appears in the books-- the Warshrine, the big monsters, and even things that the internet consistently praises as "must-haves" like Dragon Ogres, are all things you don't really need.
At 2000 points (with the last book-- I just got my copy of the new book today, and haven't had a chance to build lists yet), I ran a Lord, a pair of heroes, and three units of 19 Warriors. And I slaughtered the world. There's very little that can actually stand up to Warriors of Chaos in a fair fight, and if you are careful to bring the defensive equipment (and magic, this time around) that you need to ensure that your Warriors don't just get themselves shot or flushed by some miscast 6th spell, they're awfully hard for other armies to address.
This time around, units seem to be overall cheaper, if only because access to useful magic items has somewhat dwindled. So you'll end up with some points to play with and bring a "special" unit along in addition to a rock-solid core-- regardless of what category the unit comes from, anything that's not a big unit of Marauders or Warriors is a specialist unit. I'd pick one that you like the look of, and bring it along-- Ogres, Dragon Ogres, Knights, Skullcrushers, and Trolls are all fairly similar at the end of the day; Chosen and Forsaken can be taken interchangably as far as their role in the army goes, and the other stuff... I'd honestly just skip, because it ends up with a bulls' eye painted on its forehead. The big monsters are all well and good, and they're all cool models for the most part. The problem you run into is that every artillery piece the opponent has ends up pointed at them, and they buy you a turn where your Warriors aren't under ranged fire at best, in my experience. I've consistently found it's better to just bring more Warriors, rather than fiddle around with the big splashy stuff. The Warriors you can rely on to get the job done, even if the unit gets depleted from magic and/or shooting. Other stuff... not as much.
IN THE US? ASK ME HOW TO GET 10% OFF GAMES WORKSHOP PRODUCTS!