If you're going the cloth route, it is a bit expensive initially (anywhere from $100-$400 for diapers enough to last you the next two or so years, the average is about $200), so the best thing to do is some research and start ordering/buying stuff a little at a time now so you'll be all set :) If you're going disposable, I would suggest stocking up on later sizes, especially size twos. They don't stay in newborn sizes or size ones very long. And the worst is not using diapers :( Especially because you end up spending about $1700-$2500 on disposable diapers over the course of your baby's diaper time.
I'm going to do cloth diapering, and I'm so excited about it! With my first, all I had was the very basic cloth stuff, but this time around I'm going to get some fancier stuff and re-make some of the stuff I already have. And I have my own washing machine this time, which makes it way easier. :) Though I know several people who do the laundromat thing with cloth diapers.
I'm getting so excited for this baby, and I still have 21 weeks til due date. :P I already drug out the stuff I used with my first, and am getting ready to spruce it all up for the baby :) That's another nice thing about cloth, you can reuse it for subsequent children. I gave away some of my cloth stuff tho, so I need to add to my collection.
So, what do you think, ladies? If you are wondering about cloth diapering you can ask me, or go to one of the many cloth diapering communities here :) I highly, highly recommend it. It's not really much extra work, just extra laundry instead of extra garbage.