If you're really serious about reducing your reliance on diapers, even with your impending newborn, check out www.diaperfreebaby.org. Elimination Communication (EC) has been a wonderful experience for us (I only wish I'd known about it sooner - we started when DS was 10 months). DS has been in underwear full-time since he was 19 months, and for about six months before that, he was in training pants with me and only wore diapers when he was with the nanny.
woohoo! we are finally doing it...she started going well at around 34 months, even though she peed in the potty sporadically starting at 27 months. Now, at 35 months, she goes to the potty 90% of the time on her own. Woohoo!!