Ask HN: What currency is best for a UK startup to charge in?

So i've been working hard on my startup, and i'm now ready to see if i can convert some of these beta users into hard cash.

But which currency should i display on my pricing page?

The product really doesn't have any territorial boundaries, and i've chosen a payment processor that can handle £ or $, but i just wondered what people's thoughts were on this?

My thoughts are that globally $ is better, but we're based in the UK so would people expect a price in £, would that put off other countries?

General thoughts please :)