[coldphoenix]

@jsl

ND stands for Neutral Density...all it is basically is a filter you throw on the end of your lens that stops alot of light from getting to your sensor, and thus enabling you to use longer shutter speed--and might I add as well, it does so without affecting the color, hence the name "neutral" density.
That is to say, if I want a 5sec exposure on that sort of shot, even if I max out my other settings, aka stop the aperture down to f/22 or whatever its max is as well as decrease the ISO to its lowest usually 50 or 100...you're still going to be getting too much light and the shot will be overexposed. Solution is to use an ND filter which are rated in the amount of stops of light you will lose. Its good to get a couple smaller ones like 2-4 stop ND filters, because you can always stack them and the effect will be additive.
Another handy filter to look into are circular polarizers, but more in line with this conversation are the GND, or graduated neutral density filters. Which as the name suggests, is a filter with a gradient from clear to gray(neutral density) and thus allow you to expose properly for a scene with a vast lighting difference such as in the case with sky and foreground.

I'm actually not sure on your second question, though I do know I've only ever encountered the f/32 on wide angle lenses and only when they are nearer their shortest focal length.

And lastly, thats a tricky question to answer for all types of scenes you may be shooting. Afterall, its the whole art of photography to attempt to capture what it is you see. Theres no 1-2-3 solution to your problem, what I'd recommend is playing around with your white balance and HSL (hue/saturation/luminosity) settings in post process.