I agree - the iron pills constipated me fiercely that I then had to take stool softeners, which still didn't help, and worst of all I STILL had low iron. ARGH!!!!!
This time, I bought a bottle of Floradix and have taken a dose maybe 7-9 times throughout my pregnancy. Just kind of when I felt like I should or needed it. I plan to have it very handy when I birth, and try to remember to take at least one dose during labor (more if I have a long labor).
I haven't taken any prenatal vitamins this time and I've felt completely fine. I haven't gotten the "pregnancy symptoms" like crazy hair and nail growth and stuff like that, and I realized those symptoms were actually reactions to the vitamins. I'm not saying they aren't good, but I know the vitamins I need, and what is good to have more of during pregnancy, and I know what foods have those nutrients/vitamins.