You won't get much if at all, because 16GB formatted capacity is around 14.5GB out of which some space is reserved for various partitions such as the ROM itself and data, cache, etc.
Unless you want to screw around with partition sizes, you won't get much.
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(Stock ZVC Rom)
Past Devices: HTC Butterfly, HTC One X - Tegra 3, LG Nitro HD, LG G2x, Samsung Vibrant, Samsung Galaxy 3, Nokia 5800, Motorola Razr Maxx, Palm Treo 650