Well, I have all my camera gear insured on my home policy by LV. It is covered for accidental damage in and out of the house, theft, even when it is in the car so I have never been that tempted to look a specialist photo insurance.
I am with Glover and Howe. I have no idea if they are the cheapest but they paid up recently when I managed to drop a 10D into the Atlantic from a cliff in the Falklands
They paid me £520 (less 10% excess) - the cost of replacing it with a 40D from Warehouse Express. Of course I had paid a premium based on this amount but I was still very pleased with the service I got.
I think it is important to check that any cover is "new for old" like this as the 10D was worth much more to me than the replacement cost of a second hand one would have been.
Only tiny issue was actually not proving it had happened but that I had the camera in the first place (!) so worth making sure you keep receipts or whatever.