I also think it's very important to consider all of your options and not necessarily decide ahead of time that you will take pain meds. What the childbirth teacher said about the epi messing with your natural pain relief hormones IS true, so while you might not have more pain while it is in place and working, if it doesn't work, or when it wears off you will be in far MORE pain than you would have otherwise been. On top of that, it does increase your chances of having a c-section (especially if you get it before you are 5 cm dilated), as well as potentially dangerous low blood pressure (I had a client who needed significant doses of major medications because her blood pressure was so low she was barely conscious), and breastfeeding problems too.
That said, there are times and places where an epidural can be helpful. The book "Birthing From Within" actually calls it a "compassionate epidural". I had an epidural with my second birth, and I have no doubt that it SAVED me from having a c-section. I was stressed and fearful and worried (DD had major issues that would need surgery after birth), and I was incredibly discouraged by my perceived lack of progress. I got the epidural, and within 20 minutes my water broke on its own, and 25 minutes after that, I pushed my little girl out.
Another important note, there are different kinds of epidurals. Most hospitals I have been to laugh at you when you ask for a "walking epidural", but a lot of anesthesiologists will give you a "light" epi, and if you can get one where you can give yourself a boost if needed (they will give you a button to push), you can also control the strength of it. My epidural was very light, I was able to feel each contraction, I just didn't have pain from them, which was very nice when it came time to push because I was able to feel my daughter coming down. I also didn't need a catheter with my epidural, for which I was very thankful. I was up and walking within 1/2 hour - 45 minutes of the birth.