The breastfeeding drill sergeant. This is the person who will not let you give up -- no matter how tough it is. Don't even think about formula! You have to keep at it. You can do it. Her standards are impossibly high, but she believes in you.
The laissez-faire feeder. This is the "it's okay if you ..." kind of person who says things like Don't worry, you can supplement with formula every once in a while. We all did it. Give yourself a break. You need to hear this to keep going. Breastfeeding is partly a mind game. You'll undermine your efforts if you get too stressed out over it.
The boob-whisperer. This is the would-be doula, the friend who is obsessed with all things pregnancy-baby-nursing related. You literally cannot ask her too many questions because she loves this subject. And she's got gobs of nursing-induced hormones running through her system that make her especially sweet and patient.
The colleague. If you're lucky you'll know another woman who has a baby around the same time you do and who is in a similar home/work situation. In my case, one of my co-workers had a baby about six months before I was due. I was able to pick up a lot of tips on pumping at work from her before it was my time. It was also great to have someone in the office who knew exactly what I was going through as a new working mom.
The bottler. This is the friend who tried her best and ended up with a dehydrated baby in the emergency room. It may turn out that, for whatever reason, you just can't breastfeed. You'll want a friend who completely empathizes and can assure you that your child won't grow up a sickly, half-brained sociopath if you feed her formula.
The significant other. In most cases this is the guy who knocked you up in the first place. Or the woman who agreed that you'd try the IVF first. My daughter's fetched water, brought pillows, delivered shoulder massages, and did whatever it took to keep the baby-feeding machine going.!