One more thing to add:

I agree that you should buy as much as possible in the US-much more selection, way better prices... But, if you buy electric appliances (breast pump, baby monitor, etc.) make sure the appliance can handle 240 volts. I did some research on this, and while pumps generally were 110/240, small baby-related things such as monitors and bottle warmers were not 240 volt compatible. You can bring converters, but for relatively inexpensive things, the cost of a reliable converter may be too much (and the cheapo travel converters will eventually blow out on you! Usually when something important is plugged in...)

Also, if you are worried about bisphenol-A, you should buy bottles in the US-they are not widely available here yet.