Taking some time to research, I found that, the Bible records incidents of three different types of "giants" or men of extraordinary size. these where the Rephaim, Anok, and Nephilim.
We all know the story of David and Goliath?(1Sa 17:4-7) Goliath was over 9 ft 5 inches tall. The head of his spear weighed 15 lbs (6.8 kg), and his scaled chain mail weighted at 125 lbs (57 kg)!
Goliath, however, was a title and not a name, these mercenaries of war where part of the Rephaim. More accounts of different Rephaim appear in the bible. There was Og, King of Bashan. Ishbi-benob (2Sa 21:16); Saph, or Sippai (2Sa 21:18; 1Ch 20:4); Lahmi, Goliaths brother(1Ch 20:5); and a man of extraordinary size whose fingers and toes were in sixes, totaling 24 (2Sa 21:20).
The Anok where an even bigger mystery. The Israelite sent out spies into the territory of the Anok, these spies came back appalled and frighten from what they have seen. They reported they felt like grasshoppers among men of extraordinary size, and believed they where Nephilim.(Nu 13:33)
The real Nephilim, however, where already long gone (Ge 6:4). These guys where even scarier. They where a the offspring of materialized angels, and Human women. Any idea how power a single angel can be? There's story that tells of one angel that killed 185,000 of the Assyrian army in one night! (2Ki 19:35) The Nephilim appear in all sort of mythology around world. From the Mayas, to the greek. Those guys are really bad arse.
Whether you believe in the bible or not, it's easy to admire the awesome stories it contains. Reading about these giants of old have definitely inspired some character creations on my end.