Actually, contrariness aside, the original movie ("Episode 4" AKA "Star Wars: A New Hope") is quite good. I would recommend watching the unaltered version, however, not the silly re-release. (The extra ground traffic in scenes was cute, but changing certain events, not so much.)
Really. It was a good movie. I promise I won't tell anyone you've seen it.
The other two "original" movies were ok. I liked the ending of the third one ("Episode 6")
I could not, in good conscience, recommend any of the "new" movies ("Episodes 1-3"). They could have been great, if not crippled by gross commercial pandering and absurd casting. One blog I used to follow actually published instructions for how to fast-forward to the "good" bits, reducing the time for the whole trilogy down to about 1 regular movie length. If such an edited version were made available, I'd probably buy and watch it, as there was some cool stuff in there.
Plus, the "Robot Chicken" Star Wars parody won't really make sense until you've seen the original movies, and that's a real motivator.