I got asked this question today. I've been around here long enough to have heard all the supposedly "true" origins of the company's name. The most frequent assumption I've heard is that the company is named after the "F5" key on a standard keyboard. There are some handy uses that the F5 key does provide. The one I use most frequently is to kick PowerPoint into presentation mode (you can also make the screen go black or white with the "B" or "W" keys while in presentation mode - which comes in handy for discussion or white board breaks). But, being the basis for our company name is not one of them. F5 is named after the highest rating on the Fujita Scale. Just as earthquakes have Richter and hurricanes have Saffir-Simpson (bet you didn't know that one!), tornadoes have Fujita.
You're correct about the source of inspiration. Another company name that was inspired by a movie is Packeteer. The movie in their case was "The Rocketeer". If you look at their logo, you'll see that it is made up of two little rockets flying around.
The Name F5 represents highest intensity tornado which has incredible damage capacity and it measured on Fujita scale starting from F1 to F5, So the idea is to represent that these Big IP Devices has incredible traffic processing capacity so the name is "F5" !!!
