I just got my Galaxy from eBay. The auction said it's 16GB, but I am afraid I was a fraud victim; I'm checking at Settings->SD card and device storage->USB storage, and Total memory says 5.01GB.
Am I missing something?
My Galaxy S Vibrant has 16 GB internal SD storage, and
Given that 8 - 5.01 is also ~3, I would say that you have an 8 GB model on your hands. Checking with Titanium (requires root) or something else might be a good idea.