650D versus 60D with prime lens - first DSLR advice please!

I have narrowed it down to the 650D and the 60D – they are available for pretty much the same price at the moment here in the UK with the 18-135mm kit lens.

The 60D appeals as I understand it has a degree of weather-proofing – can anyone tell me whether this includes any element of dust-proofing as I intend travelling with the camera to places which potentially may be dusty (e.g. India & Burma).

In terms of lenses, I am looking at the 50mm f1.4 and 50mm f1.8 lenses mainly with a view to getting good pictures in dim lighting of my niece/nephew but also for evening shots whilst travelling.