I also use circular needles for everything. It is much easier on the wrists. Knitting in public with them is funny because most non-knitters have never seen them before and are very confused, lol.
I do use straight needles when I'm teaching people to knit, though. It is kind of like a weeding out process-- if you're serious enough about it to use the straights and the crappy yarn for a while, THEN I'll introduce you to the good stuff!