Best Dual SIM Mobile Phone - Support for at Least 3G on Both SIMs

Hi,

I am after a value for money Mobile Handset with Dual SIM capability.
Got a Work phone (Vodafone) and personal phone (Optus) and will make my life heaps easier if I don't have carry, charge and look after two different handsets.
Happy to get a grey import.

My budget is around $150 but happy to increase a bit if there is good value.

Specification wise -

1. Mainly use the phone for making and receiving calls only.
2. Good battery life is something that I consider important.
3. Other than that not too fussed.
4. Australian stock will be good but Grey import will do as well.

Look forward to your suggestions.