Like most I think I picked up bits as I went along, although I did leave until after 20 weeks. My parents bought the cotbed and DH's parents bought the pram, which we left until about 35 wks. As soon as I was past about 25 wks I think my parents gave me a different something or other that they couldn't resist that particular week!
Be careful about what
you buy as well wishers will probably buy you baby clothes and they will probably buy "newborn" size which baby doesn't usually wear for very long, so it's good to buy some 0-3months stuff too.
I had everything new as I didn't know anybody who could hand stuff down to me, I would have accepted offers of things had they been forthcoming though, like Joh, the only things I wouldn't except second hand are car seats and matresses.
I didn't buy any feeding associated equipment (bottles, steriliser etc) as I was planning to feed myself, in hindsight that was pretty silly, but I was very lucky that all went well in that department
Second time around I had newborn size babygrows that hadn't been used with first DD (8lb 9oz) but second DD was tiny (5lb) so my Mum had to go to the shops on the day she was born and get some "tiny baby" size clothes and nappies.
To be honest, with the internet and speed of deliveries these days, you could have your baby and if you were missing anything you can have it on your doorstep within a day or two.
If I can give you my two recommendations of things I have found to be faboulous, the first is an in-ear digital thermometer (I have the Braun thermoscan) and Grobags

Happy shopping, I loved baby shopping

