One of the big purchases you'll need to make for the new Black Magic Cinema camera is a solid state drive. I opted for the 120GB Sandisk SSD to start out, but quickly realized I need more to support the RAW video mode. The Sandisk 480GB is a great option and currently lists for $345 Amazon (seen here). It's a drive that I think most people will end up buying if they are shooting with the BMCC.
This Sandisk 480GB is one of the SSD Drives recommended in the Black Magic Cinema Camera Manual, so if you're thinking about the BMCC, this drive is currently on sale for $300 dollars for the next 8 hours. Check it out via eBay (click here).
Sandisk 480GB SSD Solid State Drive for Black Magic Cinema