[Parallax]

Well, if you are using film I would suggest shooting at whatever ISO is marked on the box the film came in.

(I know, sorry. I just couldn't resist that one. )

[johnmflores]

If you really want to shoot wide open F1.4 in daylight then you'd better invest in a ND filter, probably one that's worth 2+ stops. It partially depends on what your fastest available shutter speed is.

And regarding ISO for digital shooters, I used to shoot sun up to sun down at base ISO, but I've just started letting it float around a bit more - up to ISO800 in some situations. This approach is giving me a little more latitude to select an aperture and shutter speed that meets my needs - for example, bumping up the ISO instead of slowing down the shutter to avoid motion blue of the subject - with (to me) negligible difference in IQ. So what if I lose a little shadow detail - it's only one part of the photo and most of the time not the most important part.

This is a personal preference of course, YMMV.