I have been with freeserve/wanadoo/orange back since dial-up, paying £17.99 per month. I just swapped (or I am in the process of swapping) to Sky - free for 6 months then £10 thereafter, for their unlimited service. I think that deal ended last week though.
Just waiting for the swap over on Thursday. Hopefully it'll all go swimmingly.
The reasons I changed were: a) I was fed up paying £17.99 a month and I have experienced a few outages with Orange over the past few months, all in the evening, all for more than an hour.