thank you all for your supportive comments
I've travelled to many countries (Mongolia, India, Nepal, Tibet, Venezuela, Laos, Cambodia, Indonesia...) Ethiopia was surely the best trip I've ever been to. I have to say that by taking pictures you can get closer to local people than if you're just an ordinary traveller. I really like it. Travelling and photographing is my hobby so this was just my private trip.
I've been considering visiting Ethiopia for at least 4 years. I've seen a lot of beautiful pictures.
I've gathered some information about the trip at first but I didn't think the travelling would be that safe and comfortable. The south of Ethiopia is safe, that is surely not true about Sudan, I definitely wouldn't go there.
We had arranged a car 4 x 4, a driver and a guide, booked accomodation in Turmi, Jinka and Konso from where we drove to particular villages by car. When I was booking the trip I asked Ethiopian travel agency for an experienced guide and possibility of flexible programme because of shooting pictures of the local people. I was very pleased with accomodation – warm water, electricity. I had 2 S2 batteries with me, the battery life is excellent.
These days there is dry season in Ethiopia so there's a little problem with the dust but it's bearable. In the rainy season some areas are closed and there are plenty of mosquitos.
About the backup storage system and laptop – I didn't have anything - only 4 x 32GB CF sandisk. I'll have to buy a macbook, it surely will be useful.
Thank you again everyone