Predator Tank
The Predator is the Main Battle Tank of both the Imperial Space Marines and the Chaos Space Marines. Based on the rhino chassis, it is just as customizable as any Imperial Vehicle. There are three common versions, and other variants are occasionally "discovered" as "relics" by the Machine Cult. Well, either that or the Spess Mehreens nick the guns from a Devastator squad and put them on a Predator in new and interesting ways.
Destructor Pattern Predator
AKA, the Predator Destructor. The Destructor is armed with a turret-mounted autocannon, and can be fitted with sponson-mounted Heavy Bolters or Lascannon. Destructor Pattern Predators are the only version available to most Chaos forces. They can be fitted with any vehicle upgrade available to the SM or CSM.
Annihilator Pattern Predator
AKA, the Predator Annihilator. The Annihilator is armed with turret-mounted twin-linked Lascannon. Like the Destructor, it can be fitted with either Heavy Bolters or Lascannon in its sponsons. A Predator Annihilator with Heavy Bolter sponsons is considered by many players to be the most efficient build, and so it is the most popular among tourneyfags.
Baal Pattern Predator
The Baal Pattern Predator is armed with either a turret-mounted twin-linked Assault Cannon, or a Flamestorm Cannon, which is like a Heavy Flamer but bigger. The sponsons can mount either Heavy Bolters or Heavy Flamers. Basically, point this motherfucker at Tyranids and watch your opponent struggle not to cry. The Baal Pattern is only available to the Blood Angels and their descendents. The Blood Angels found the STC for the Baal Pattern during the Great Crusade, but when asked to share it with the Admech, they decided to take their Baal and go home.