i'm a 5.5 too, and when i tried on 2ct it looked so gaudy and fake. 1.5 seems to be the perfect size for me - these were all round solitares too.
Same here. I think the biggest I could pull off is a 1.5 ct. Im kind of a "dude" in a lot of ways, and while the bigger stones are great, I already can't use my hand well out of fear when I wear my rings now and the e-ring is just under a carat. Anything bigger is liable to blind me in my right eye from over-louping and give me a heart attack.