We finally got a new roof this week and it really transforms the house.
We chose a GAF 50 year roofing shingle in the Birchwood colour. We hope that the light colour will reflect light and result in a cooler house. We had also read verious articles indicating that dark roofs contribute to global warming and while this roof is not white, it's the lightest generally available shingle we could find. There are some specific light-reflecting roof shingles on the market, but our roofing contractor told us that they were in such demand that he would not be able to get them before the end of the year.
The plywood cladding and roofing shingles are delived to the roof by this conveyer on the back of the delivery truck which is quite impressive to watch.
Side note: just after taking this photo I fell into a hole in the garden, one of the perils of living in a building site. Fortunately nothing but my dignity was injured!