I go for a Columbus Direct annual policy as they seem to be one of the few who will cover an epileptic for my more adventurous travels without charging an absolute fortune or needing the nurologist to write to them. I have had to claim once (return trip from Zambia delayed, then cancelled, etc etc, and medical problems) and they were very good at sorting things out and paying up.
Funnily enough adding Mr Womble to the policy is really cheap after we have got me covered for high altitude trekking and white water kayaking!