For me, I would definitely get the shallower (8") depth. I don't want to have to bend over that far to reach the bottom!

My sink is 11 and maybe 1/4" including the counter top. I'm 5'5" and I find that depth to be perfect. I do have a grid in the bottom which subtracts close to an inch. I was thinking just last night how much I like the extra depth - I was using the sprayer to squirt out the stuff that sticks in the strainer's small screen grid that I'd been using to blanch and then cool squash for freezing. All the spraying water stayed in the sink vs. all over the kitchen. I also had the really big chili pot down in the bottom of the sink to wash it and all the other stuff I used to make (another!) batch of berry jam.

I've never filled the entire sink with soapy water to wash. I either use the largest pot that needs washing or I just put the soap on the sponge. If something needs soaking, I leave it to soak before washing, often with soapy water which then gets used for washing everything else.

I say it depends on your needs. I got the 10" depth Single
Silgranite II sink because I wanted something to bath my dog in. :)
I also wash dishes like suzannesl.

I'm 5'2" and I love my 10" deep silgranit sink that is undermounted to my 3cm granite. LOVE LOVE it!

I'm 5'3" and I got the 8". My old sink was very shallow by today's standards, and the bottom of my new undermounted sink is more than 9" down. I generally put a few inches of water in the sink and then wash one item after another, so I am reaching down to the bottom. Especially at first, I really felt it in my back that I was reaching down farther. I'm more used to it now, but I think that ergonomically it's better not to be stooping. I also wash my 45lb Springer spaniel in my sink, and part of the reason I got the one I did was so that she would be easier to lift in and out.