To do 'I Feel Love' properly, you need a gigantic Moog Modular. Fortunately, this helpful japanese site has a pdf which you can download to build your own. Out of paper.
I was planning to write a 'how to' guide, like they have in real music gear magazines, explaining how to do the bassline using free VSTs and stuff. Then I tried to do it, and it was much to hard. Fortunately, I'm in good company. Trevor Horn was obsessed by 'I Feel Love' when it came out, but didn't have the technology. Eventually, he hired a Moog at great expense and "couldn't get a bloody squeak out of it." (The trick? Half speed bassline + short delay)
In 1979, Giorgio said " It's nearly impossible to compose with a synthesizer. By its nature, improvisations are much easier, so I went into the studio and recorded "I Feel Love" as it was composed. All I used was an electronic bass line and an electronic drum. That's the big difference between normal and electronic recording.
Amusing people who have covered 'I Feel Love': Paedo-bait Vanessa Mae, Bronski Beat & Mark Almond who also used most of 'Love to Love You Baby', Blue Man Group (please don't click on that link), Songs from a Random House who are the ugliest band you will ever see, and Blondie, who played it live at the Hammersmith Odeon in 1980.
CLICK FOR PT.7: MORODER'S LIFE TAKES A SURPRISING TURN