Copper pipe is best for hot water especially very hot water. The 12mm stuff is fairly cheap and easy to bend smoothly to fit. No need for solder any more as the elbows and T sections are brass with screw connectors which compress a nylon bush. Used to be copper bushes but nylon is better. Plastic is OK for cold water. Also you can use the flexible hose if you want to but I find working with copper easy enough. Waste water pipes are all plastic and very easy to cut and glue the fittings in place. There is no special skill required any more for basic plumbing work. Same applies to basic electrical work, everything is either colour coded or marked in some way. Just take it slowly and carefully and you can't go wrong doing it yourself. And if you are uncertain of something just look up how to do it on the internet and follow the step by step instructions you will find there.
