I would suggest this controller:
I just love novation stuff because it pretty much sets itself up. Automap is amazing, some controllers you have to program but the nocturn I just installed the software and drivers, opened up Logic and it all worked beautifully. Its kind of a complex system that uses the controller and its own software but it works great and I guarantee you can map it to absolutely anything you want. Plus you're not limited to only using your 8 knobs for 8 things, you can switch control mappings on the go so it is reaaaally flexible.
Might also want to look into getting a copy of Native Instruments Massive and FM8, those are two great synthesizers that about 90% of dubstep producers use. Sylenth looks like a beast of a synth though, so you could probably go without.
And for some great production knowledge:
(excision and a lot of other producers are on dubstepforum, but the big ones rarely post)
and for some seeeerious discussion:
READ THE FAQ ON DOGSONACID. There are links to loooong Q&A threads where people interrogate the fuck out of some of the biggest names in DnB including Noisia, and many other famous producers that you probably know much better than I do.