I use session drummer a lot, some using the inbuilt samples and the rest custom made from real synths & sampled in.
I mainly do EDM work now such as Electronica & some other stuff like Trance, Progressive House, etc. You may find that certain genre producers get a basic snare & modify it using tune, tone, filters, reverb, etc to achieve that hard sound so you could try & experiment. Otherwise you could always buy into one of the many drum sample libraries such as:
Vengeance - refx.com/products/vengeance/samples or
Prime Loops - primeloops.com
Many pro producers swear by Vengeance but it does mean they've been over used, to death actually but if you want that commercial chart sound, that's the ones to use! Personally, I like to steer away from sounding ubiquitous & make my own variations which I suppose you could do by modifying some of their samples.
Then again some people would probably say that my stuff sounds sh*t so what do I know!!!
I'd also try "Google-ing" "free dubstep samples" as there are many producer & VST-Plugin sites which have loads of free sample libraries, some of which are as good as the pro sample libraries but they're for free so you've nothing to loose other than time auditioning them.
You pays your money & you takes your choice...