Obviously this is personal opinion and everyone's tastes vary, but I like to really contrast my window trim and fascia from the rest of the house. Done with a good color scheme, it really pops.

Online samples are difficult to match but my house is similar to the Sandcastle and I did my fascia and trim in a dark Navy blue (but did in aluminum).

My personal taste to contrast the Sandcastle would be (staying with SW) would be the Cheyenne Red. I'm staining a shed using Cabot's in similar color to Sandcastle and doing the trim in their Newbury port blue (its more navy blue than it appears online.)

Some of the SW dark drown's or greens would look good too, but I'm not a general fan of those colors. I don't care for SW blue's.

Do a google search for "color wheel" to find great combinations of complimentary, contrasting, etc colors.

I do have a tendancy to like my siding lighter and my trim dark in color schemes.

Thanks for your input. We're having new gutters installed also, so I found a gutter color that works nicely for trim.