Currently on a Lenovo Yoga, being the cheapest range with a decent keyboard. However, it's a holdover machine. The longer term plan is to buy something designed for Windows 10, probably next year. (Windows 10 isn't finished and the hardware isn't here yet.) So, at this stage, I don't know.

Re Bing apps, they were created to get some stylish-looking apps into the Windows Store, to get Windows 8 users used to apps, and to provide examples to third-party developers. I expect them to be installed on demand, and a couple of them are already scheduled to be discontinued. They're really not worth obsessing over.