You will have increased stopping power with the car in neutral, or with clutch in, as the engine isn't driving the wheels anymore, so less resistance.
Stalling, IMO, is not likely, but is possible. If you are dropping into neutral for a stop at 50/60mph I'm presuming that you are still above idle when you begin applying the brakes ... also I don't think you could stall a race car that easily either doing this as I would imagine idle would be well above stalling point. If you have an older vehicle which has a somewhat erratic idle, or for example the AC is draining power, then there is the possibility that you will dip just enough to get a stall. On a healthy engine I wouldn't imagine it happening anywhere near often.
