I had the triple test with dd my first, because I was ignorant and it was an opt out kind of thing rather than an opt in thing. With ds in a different area it was a more opt in thing where you had to make an appointment etc, I think this is preferable, made me think a lot more anyway.
I didn't go for the triple test with ds, I reckoned that the 20 week scan would hopefully throw up anything life threatening (I know not 100%) but I also knew that I would and could not terminate for Ds and Sb.
As it happens I reckon ds did look a little ds at birth, and I clocked a few dr's mooching in and taking a good look at his palms etc.
It's hard because obviously Downs Syndrome has a whole spectrum of effects, some will be at the severe end some at the mild. I could not live with myself if I terminated for ds though, it's a totally personal decision.