First of all, everyone buying a laptop needs to read this article on laptop branding.
Secondly, the "best" laptop is always completely subjective. You need to know what you want your laptop for. You will always pay top dollar for the latest and greatest spec, so downgrade your spec a little bit and you can save a large amount of money. You need to balance that with future proofing your purchase however, as laptops are notoriously difficult and expensive to upgrade.
You could do worse than scour the notebook review forums (especially the "What Laptop Should I Buy?")
One of the intangible attributes of a laptop is it's build quality. Products like LG, Asus, Sager etc. have good reputations for the build quality of their laptops and are priced appropiately.
A trip to the US is a great time to save a few euro purchasing a laptop. Bear in mind you will more than likely purchase a laptop with a US keyboard but it really does not take your brain long to reprogram! (I can quite comfortably switch between UK and US keyboards. Brains are great!). The second thing you need to be aware of is the US power supply, you will need to get a UK power supply for the laptop or a converter to carry around with you when you return.