Can you recommend a site for online questionnaires?

I need to gather some principled data from a specific group of people who live on the other side of the world from me.

It is necessary that the questions be readily answerable, so I would far prefer to give out a URL to the questionnaire rather than make it one distributed by email – I want as much participation as possible from a limited group of possible participants.

I do not want to collect email addresses – the questionnaire must be absolutely anonymous. I do not want to participate in the collection of email addresses for marketing purposes.

I am willing to pay if necessary. Ad-free would be nice. I will pay a reasonable (under £50) fee.

The questions will require yes/no and variable scale responses, with a free text box should the participant care to comment.

It would be great if the data I received were already broken down for me in .xls or .ods formats. I will do the analysis; I just don’t want to spend hours copy’n’pasting data from a word document into an application that will allow me to manipulate what will primarily be numerical data.

I am fully aware of Google; I would like recommendations from Flutherites, preferably from user experience.

Thank you very much (in advance)!