I am a warrior for circular needles. I just inherited some straight needles that went into my archive but in 30+ years of knitting I have never bought straight needles. (I did have some to start with). I do not know anything you can do on straight needles that you can not do on circs. (Or am I wrong now?)
I love circs for ergonomic reasons: since the stitches stay closer to the middle they do not have so much leverage and therefore keeps the shoulders carry less.
That is my personal preference and opinion.
Continental Knitter with passion, pretty busy and always onto something new.
I have been away from the forum for a bit, but I am still around!