I strongly agree with EB's three main tips.
1. Food >>>>>>>> any other gift, card, tiny clothing, flowers. Those first few weeks your life has been flipped upside down. Finding the time and energy to make food is near impossible.
2. Two things that always came up in the books I read were the following; 1. Babies are tough and resilient. 2. All babies are different. Googling every single new thing they're doing will drive your wife crazy. Try to avoid it as much as possible. If you're really concerned you should be talking to your pediatrician.
3. Anything involving pumping is incredibly time consuming for the wife. I know formula is expensive, but if breast feeding isn't working I would recommend it to anyone. The mental health of your wife is more important than the dollars you will drop at the store. The week after birth my son and my wife had separate hospital stays. While they were separated we obviously had to feed him so he lost all interest in breast feeding during that week. So my wife pumped for about 2 months after that. When she finally threw in the towel our whole lives changed. She had more energy, was in a way better mood and was now able to spend so much more time with our guy.