I've just ordered a new motor, from Xiong Da Motor. This is a bike motor with two gears. It means that for going up hills and suchlike, I can change to low gear and got a lot of torque; for travelling on the flat, I change to high gear and get more speed. It's a very neat idea, and it's been well recommended by expert ebike users on the forums I visit.
It's only 250 watts, so it's within the UK legal limit, and I'm also hoping that it's light, so the bike will be easy to lift. The specification says it's 3kg, which sounds good.
The controller is sinusoidal. Most controllers deliver power in a square wave; sinusoidal should mean a quieter motor. and it comes with a switch for changing gear, and an LCD display
It's just a motor, no wheel. When it arrives, I'll have to lace it into a rim, which means I'll need to buy spokes, but I can't get them yet because I don't know the length I'll need. I've laced a motor into a wheel before, and it's a lengthy and fiddly job. That's because you have to get the spokes just right; if the hub is slightly off-center, then the ride will be up-and-down. And so you have to go through a procedure known as "truing the wheel", which involves tightening and loosening spokes until it's all just right. Last time I did that, it took me several hours. Fun to come!