If you're planning on breastfeeding, you want to get a bottle that has the same suck as breastfeeding does. Most bottles require a different type of suck, which can lead to nipple confusion...or the baby just refusing it all together.
When I got prego this time, my baby was only six months old (it was a super surprise pregnancy!). She was 100% nursing, and my milk took a really hard hit from the pregnancy and wasn't enough for her. We tried Avent bottles, which are great, I'm sure. But my baby wouldn't take them.
We finally found Breastflow by the First years:
http://www.thefirstyears.com/wps/portal/breastflow?xcid=PS
These are AWESOME. It is the same suck as breastfeeding. I think all breastfeeding moms who want to also give a bottle at times should look into these. They were a life saver for me because my baby wouldn't take any other bottle. You can find them at Target and probably Wal-Mart. So they are easy to come by. I highly, highly, highly recommend these. Some think that some Dr something bottles are better. No, they aren't. They just have the milk flow slowly, which Breastflow has two types of bottles. Ones for newborns (slow flow) and one for older babies.
Any type of bottle you get, if the suck is different than nursing suck, you are going to risk nipple confusion if you offer it in the first month...well, except for the Breastflow bottle since it's the same suck. So, you might want to be careful of offering anything else, other than nursing, for a while.