My Dad was an atheist and said if a 'preacher' was at his funeral, he would come back to haunt us!! We had a non religous service at the crematorium. As Dads coffin was carried in, the opening bars (the quiet bit) of the 1812 Overture were played. (Most crems are quite happy to play any music you supply). Mum led the 'service', talking about how she met Dad and stuff. My brother talked about him as well and my sister read a poem. I couldn't think what to say, so I thought it best to say nothing. Dads coffin then went behind the curtains to the end (cannons etc) of the 1812. Some people said it was the best funeral they had been to. Basically you can do what you want,