Should I use a US-based webhost?

Most of my users and Google referrals are expected from the US

[Lysander]

I currently use a UK-based webhost that I am very happy with. However, the website I am preparing to launch really relies on US-based surfers and Google referrals; is it worth going through the mammoth task of looking for a reliable US-based host, or should I just stay with the British one?

I am concerned about two things:

(i) Will Google give priority to US-based websites when people in the US do a Google search?

(ii) If I move to the US, will having a British host be a problem?

I would rather get this right before the launch than have to move the entire website and database later, which would be a nightmare.

Thanks.

[Essex_boy]

Dontthink G cares to be honest.

Although in England I use US based webhosts as they are the cheapest I can find.