If you contact your local council, they may give you a starter kit for free!
Otherwise you need:
a bucket with a tight fitting lid
3 wraps in each of the sizes (these don't need to be washed every time, just allowed to dry between uses)
For the actual nappies you need to decide if you want to get a onesize nappy which will be used for the whole life of your baby, or if you want to have a couple of different sizes more like disposables.
I used motherease one size, which were great from about 3 months up, but a bit big on my very skinny newborns.
I also had a variety of other washables - I really liked fluffles (2 sizes) but I think they are no longer sold.
Anything made from bamboo takes ages to dry (over a day sometimes, depending on the weather). I had different brands in size one and two, but the same problem.
I would also recommend poppers, as they seem to hold together better than velcro or the ones you use nappy nippers with. I feel this especially strongly with the wraps.
You will also need liners. Flushable IMO are the only way to go (who wants to scrape poo off?) but you can wash them a few times before they wear out- you are advised not to do this in case it clogs your machine, but I've never come accross anyone who has had a problem with that. For older babys I like the one life ones, but for breastfed poo you will need something a bit thicker try ultraliners (300 saw me through dd2).
Hope that helps - also www.thenappylady.co.uk sell everything and give advice.