It's a fantastic sport to get into. I got my dad one for an xmas pressie a couple years ago and when we took it out on boxing day I was hooked! I had to immediately go and buy myself one too.
Be aware that it is an expensive hobbie. You start with 1 small cheap kite, and before long you are wanting bigger and bigger ones for low wind days and jumping etc, as well as wanting a buggy or board.
As far as helmets etc it will kinda depend on the size of kite you have and the wind you use it in really. for your first kite a helmet is probably overkill as you will start in low winds with a smallish kite and just find it tires your arms out a bit, rather than dragging you about the beach. However I wouldn't get into my buggy with one of my bigger kites without my helmet etc.
oh if you do get into it and fancy buggying etc then make sure you get insurance and also check that you are allowed to buggy where you want to fly as there are beaches around where it's banned by the local council