I started buying stuff around 20 weeks. Like most of the other girls, I buy things gradually, normally when they're on special.
So far I've got:
* singlets (0000, 000 & 00)
* all in one suits (0000 & 000)
* socks
* bibs
* 1/2 dozen wraps
* 3 cotton blankets
* 2 x cot sheet sets
* 1 x cot quilt
* pram
* sheepksin for pram
* car seat
* cot
* change table
* 1 box disposable nappies (108 pack)
* 3 doz cloth nappies & 1 box nappy liners
* 1/2 doz pilchers
* nappy wipes
* bath stuff
* Maternity pads (2 packs)
* Breast pads

I still need breast pump, stereliser & bottles.
I bought a magazine called 'Shopping for Baby' which is produced once a year and they have a checklist of necessity items and optional items which I found really helpful.
I've also been showing my mum & MIL what I've bought and getting their advice on what I might be missing. We've been given heaps of cute little outfits so far that range in sizes from 0000 to 2.

Hope that helps
Jodi