I recommend stocking up on contact lenses and any particular brands that you can't live without. There are reasonable substitutes for just about everything, but few things that are identical.

You should definitely download Skype and a free VPN before coming. Also, if possible, keep a credit card with a U.S. billing address (parents, siblings, etc.), which will facilitate some online purchases that you might want to make (Amazon, iTunes, airlines, etc.).

Also, check your electronics and appliances for their tolerated voltages. Step down transformers work, but really only for low power devices. Your plasma TV, microwave, food processor/mixer, hairdryer, etc. are probably not going to be of much use.

Good luck with the move and Happy 4th of July!