Larian made a pretty tacky mistake in its design of Act I-Citadel Level 7! The symbol on the floor is a six-pointed "Star of David." This is NOT an occult symbol and isn't really appropriate in this setting.
The pentagram, or five-pointed star, is more associated with the occult. However, (as any Wiccan could tell you), the way it's displayed has significance. A pentagram with a single point on top denotes "white magic" whereas an inverted pentagram denotes "black magic."
The hexagram is just as ancient an occult symbol as the pentagram, and both may be found in a number of early Renaissance (or late Medieval, depending upon your point of view) works, such as both the Greater and Lesser Keys of Solomon. (Definitely not Jewish in origin. They were simply "fathered" on Solomon like so many other pseudononymous occult manuscripts of the day, but they were considered among the more respectable of that group. Each has been translated into modern English.) They were again revived for use by the occult lodges in the 19th century, such as The Golden Dawn. Both are used by modern pagan groups, to a varying extent. Speaking as a trad/Gardnerian witch and Wiccan, initiated 26 years ago, I can tell you that we make far greater use of the pentagram, but that doesn't mean the hexagram is any less worthy as an occult formula. Its meaning--the greater and the lower triangle inter-penetrating--is said to show the progress of the spirit as the higher and lower nature mingle in growth. That's certainly a worthwhile goal. <img src="/ubbthreads/images/graemlins/smile.gif" alt="" />
Incidentally, that business with the "two-points up, Satanism" stuff began with Eliphas Levi, a French renegade-priest-turned-occultist in the mid 19th century. Levi was pretty learned, but he also knew he could sell better if he made up whoppers--and did he ever! Witches didn't use inverted pentagrams for anything. Modern Satanists, eager to annoy Christians as much as possible, have adopted Levi's inverted pentagram for their own use, thus making his fiction into reality. But he's the inventor of the thing. As far as I know, my forebears in the Craft used a variety of symbols, depending upon their culture of origin, but they never thought of the pentagram in any position as a tool for evil.