There is a lot of cement. Whatever color (hardy board would be my choice) siding you use, think about staining the cement to go with. Doesn't need to be all of it, just the parts closest to the house. I agree..no angled siding, but they were trying to add visual interest to the sides, so try to break the new horizontal lines up with a trellis or something along those lines.

What about shingle profile siding? That would go with the coastal charm of the architecture and work well with all the angles. I like the staggered edge panels. http://www.jameshardie.com/homeowner/landing-hardieshingle.shtml?utm_source=JamesHardie.com&utm_medium=call-out&utm_campaign=HardieShingle&LSID=HardieShingle.com for charm. A charcoal roof gives you the most flexibility in the long run for wall color.

Love this house! Good luck!!