I wouldn't take iron unless blood tests show that you're low. Iron overload can kill you and while I doubt you'd take enough to do that, too much is bad for you.
If you do need iron, we've tried almost every iron supplement out there (hemolytic anemia)and we have had the best results with this one:
http://www.amazon.com/Thorne-Researc.../dp/B00H8ZHVQQ. I was even able to raise my hemoglobin in the third trimester with this.
Garden of Life "raw iron" is also good.