Would you charge $10/mo or £7/mo !

This question might be incredibly stupid. But I was just wandering if anyone had any interesting insights on this.

The current exchange rate means $10 === £7.14

But does one amount sound less?

Perhaps its better to charge dollars, because the pound is very weak at the minute and most people may think that $10 < £7 .

The main question is: where do your customers come from? If they are mainly from England go for pounds, everywhere else: dollars.

No, not everywhere else: dollars.
When from the rest of Euro: €