OP, I didn't manage to have a home birth but I'd planned to have one and my midwife was extremely helpful in suggesting things to have in the house. Most have already been mentioned (large bucket, 2 waterproof sheets/shower curtains, lots of old towels, an old duvet cover).
I did have a homebirth kit delivered which I think had g&a and a large pad thing in...not sure what else.
The other things were torch in case of a power cut and a plug in heater so that if the baby arrives quickly the heater can be put on to warm the room quickly and not have to wait for the central heating to crank up.
I also had several bags packed (laboiur, baby, ward, food) to make it easier to find where everything was.
Because I love food so much and it was freezing I made sure there was lots of biscuits, soup, bread, tea, coffee, milk etc. I didn't know how long I was going to be in labour for and wanted to be able to munch my way through. I was also planning to bake a cake on the day, it felt nice and nesty!
The biggest challenge for me was arranging for someone to look after DS1, the thought of my mil coming to us was not an appealing one so getting DS1 to gps at the right time was the trickiest.
Oh this might sound a bit sad but I'd also dug out two balloons, one pink and one blue. I thought that once the baby had arrived and we knoew whether it was a boy or girl, dp would inflate the appropriate colour and stick it on the gate outside our house so that the neighbours knew.
All the best!