not to be too opinionated but....
7" definitely unless you're doing a small house.

I on my house which is around 2000sqft, we did the 7" on the front and clapboard vinyl on the sides, and it looks really sweet.

I've seen 5" on houses, and it looks fine, but from the street you can hardly tell its shake as they more closely resemble the clapboard.

for reference, we used Mastic building products 7" ceder discovery in deep granite.

We are using Cedar Impressions for our siding, too. We chose the 7" straight edge and the color is cedar blend. Our house will be a modified craftsman.
I have not seen this siding mentioned on this forum before, and I know vinyl gets a big thumbs down here. This siding is much heftier than regular vinyl siding, and we like the fact that it is maintenance free.

Another vote for 7".

Sidney4, what color cedar shakes did you use? We are leaning toward cypress, but also have considered granite gray and colonial tan...

The color is Rustic Blend....it has dark streaks in it that give it a more authentic look.

Sidney4, Looks good. is there a floor plan available for your house anywhere?

To the OP, 7" is probably the way to go.

Whenley, It is a design from my builder based on several inspiration photos and a list of requirements I had. The plan is just under 2400 sq feet on the first floor and 1500 finished square feet in the lower level walkout ( 4BR and 4BA). I have a pdf version of the plan I could email you if you are interested.