Another synth you should get for sure is Absynth.
It's by far the best synth I've ever used. It's got pads and other synth sounds but drums and loops that that you can tweak around with.

Try these out. They were done mostly on the Absyth and Halion.

http://s93744050.onlinehome.us/mp3/Rocksplosion.mp3

http://s93744050.onlinehome.us/mp3/StarGate.mp3