Babies who are breastfed don't need water until eating meals and then they can have a cup. Breastmilk is 88%
http://www.kellymom.com/nutrition/solids/baby- water.html
Dummies aren't a good idea if you plan on breastfeeding (nipple confusion, non nutritive sucking still has a purpose in maintaining your supply, and postponing your fertility) and the need for nipple shields is very unlikely. It's rare they are used now.
http://www.kellymom.com/bf/concerns/baby/wean- shield.html
Don't waste your money on things you'll probably never need.
Why not go along to an NCT or LLL meeting before you give birth and talk to mums with experience.
These magazies and catalogues do sell the idea of gadgets and gizmos you really don't need.
Me personally all I need for a new baby are some cloth nappies, clothes, breasts, a good sling ( like these here
http://www.bigmamaslings.co.uk makes breastfeeding discretely on the go easy) and a car seat for the car (that stays there, it's not healthy for babies to be in car seats too long).
I have 3 children...never bought bottles or sterilizer.