I'm liking the idea of black for summer white for winter, with matching items. I do that too, although I only just realised it

I also take a spare empty bag with me, as I always seem to return from the UK with much more than I left with! And even if it fits into your suitcase, if it exceeds 32kg (as mine did on one occasion) not only will they ask you to pay extra, they will also require you to transer it into an extra suitcase or bag for hold baggage, as the luggage people in the UK won't touch it if it exceeds 32kg on a single piece of luggage (which is fair enough, but had never occurred to me before).

I always travel in trousers and flat shoes, as I am usually travelling alone and don't get picked up the other end, so I need to feel comfortable.

If I am taking jewellery or valuables it always goes on me, never in luggage, as do iPod and camera.

I used to always carry my own small bottle of water on board.
We can still carry our own water on board if purchased in the air side shops (ie after passport and security controls), which I think you can't do on US flights?