I definitely concur with all of these answers, but I wanted to chime in to address the more immediate concerns which I learned with my first.
1. Now is the time to give your wife more attention than you ever have before. Every pregnancy is different, but no one argues that it is really freaking hard. Supporting your wife through what is some of the most physically demanding experiences (I mean the entire pregnancy, not just the birth) will pave the way to happier times in the future. Today she is fretting about things that you may not yet have begun to realize. At first I thought a lot of the concerns were petty (reading the books, going to classes, all the things we had to buy) but then I realized what a great opportunity there was to connect, love, respect and grow with my wife. Having your first baby puts a HUGE strain on your relationship, so building it up as much as you can before goes a long way.
2. Expect that the first 3-4 weeks are going to be a blur (with not much sleep at all). I don't even remember much from this time, I was so sleep deprived. Every baby is different, but there will be unexpected challenges. There always are. So in regards to business, find ways you can delegate responsibility to others you trust. If you can't delegate business responsibilities, find friends/family that you can trust to be there with your wife and the new baby for a couple hours each day that will free you to do what you need to do. You'll get really efficient and productive fast.
2b. Kind of an adjunct note to #2, a few fathers told me this and I'm so appreciative of it that I share it with every soon-to-be father I know: Your wife's hormones, emotions, and thoughts are going to go through absolute havoc, the likes of which no man will ever be able to fully empathize with. Just give her complete amnesty for about 3 weeks for anything she says or does. If she's distant, or says something hurtful to you, just tell yourself its the hormones talking. Chances are she won't remember later on what she said anyway. :) This little tidbit of advice shielded me from so much emotional turmoil, I can't even quantify it. (If it goes on more than a month though you should talk to her doctor. It could be postpartum depression, which is also incredibly normal.)
3. Finally, I agree with everyone else here who said in one way or another never to forget that your family is so much more important than your business. Of course it's true that you need to work and succeed to support your family, but the line between supporting them and distancing them can get really blurry if your values aren't clear. It is infinitely more rewarding to have a loving family than a big financial success. I was part of a startup that grossed over $100k in a few months, and I would rate that experience (on a 1-to-10 scale) at maybe a 3 compared to the full 10 joy I have at home just laughing and sharing love with my wife and daughter.
As far as suggestions on what products to buy... whew. That's a whole other email. I think the most important advice any man can get about this subject is on how to respond when your wife starts talking about this seemingly random $50-$250 item that you absolutely need to get to keep the baby safe. In that moment, remember that validating your wife's concerns is first and foremost. (The worst thing you can say is that you don't need X product she's talking about.) So validate the concern, talk with her about all the stuff she's learned about it, and then if/when the time comes to buy it, just be really open about the budget. The same mother-bear instinct that researches which rear-facing, up-to-3-months, 5-point restraint system, 5-star safety rated car seat to buy (and there are hundreds) is the exact same instinct that kicks in to make sure there's enough money to put all-organic, hormone-free food on the table. You may want to shoot yourself when your wife asks WHICH of the 30 types of bottle systems you think you should buy, but remember it's a great chance to connect with her on something that she's feeling very deeply concerned about.
That said, here's some specific things that worked for us:
http://www.nickisdiapers.com/ - Amazing site to cloth diapers. We saved thousands by not using disposable diapers.
http://www.amazon.com/gp/mom/signup - Totally freaking cool discounts that Amazon gives to new moms.
Me being the total tech geek, I want this for my next kid: http://mimobaby.com/