Mat:
This is a really good question. Why do some shoot in progressive and others in interlaced mode?
Well personally i like the nice motion blur between the frames that interlaced mode gives. Progressive gives a stuttering effect that I don't like.

Richard:
I'm in PAL-country and we are shooting either 50i or 25p. In NTSC (what you are using) you shoot in 60i or 24p/30p
The PAL use 25 frames per second, while NTSC use 29.97 frames per second.
So with a XL2 PAL camcorder you can only choose between 50i or 25p and with a XL2 NTSC you can choose between 60i, 30p or 24p

Thanks Per for explaining.

Richard