We are still in the process of working out what will be the best (i.e. most environmentally friendly, yet economical, safe for baby and easy to use) option for diapers.
We'd pretty much decided on gDiapers, because they allow a cloth or disposable (flushable!) option, but they seem pretty difficult to get unless you buy online.
I found this review, which is comforting, and some more links about them at diaperswappers.
An option for disposable diapers is to order some 7th Generation diapers, which are chlorine-, fragrance- and latex-free.
We still have 2-3 months before we'll need them, so updates on efficiency will have to wait.