A small slim smartphone to use for mobile trading (MT4 mobile). Which to choose?

Hello

I’m looking to buy me a smartphone to use with MT4 mobile SE (or MT4 mobile regular).

Since i’m going to use it at all possible locations it has to be quite small and handy. A decent battery time is also a must. Operating system have to be Windows mobile 5.0 or 6.0 (e.g. what MT4 mobile requires).

More than that i have no specific criteria to be met. I’m going to use it for trading only, no phone calls or nothing else. Maybe some wap surfing ocasionally.

So, which should i choose?