I've spent well over 2000 dollars on mine. I believe I have eight chaos tac-squads (6 Black Legion and 2 WordBearer), two mobs of Berzerkers, a squad of Thousand Sons, Plague Marines and Noise Marines, a five man terminator squad, three sorcerers, a terminator captain, and captain with a power axe, and the special lords for the Emperor's Children, Iron Warriors and Nightlords. I also put together a Chaos Chaplain/Dark Apostle for WordBeares out of extra Chaos bitz and Dark Angels bitz. I have a Nurgle prince and a Normal Daemon Prince, and then I have basically every major named HQ for Chaos Marines (Not major daemons though) Abaddon, Huron, Lucius, Kharne, Ahriman, Fabius, Cypher, Typhus
I plan on collecting two squads for every legion that I have a Lord for, and I also want to do vehicles for each, although I don't have all the vehicles (or troops) I want for Black Legion...and don't even get me started on the massive list of daemons I need/want