Not free but very good! Very easy. Allows the best mp3 options.
FairStars Soft - FairStars Audio Converter
Stay away from their "pro" version. buggy. Has one good feature but there is a free utility for that.
When you need to use a cue file to split a flac, use this free util. It works great.
Medieval CUE Splitter (PC)
A very simple wav to mp3 converter I like very much but don't need anymore that is free:
http://home.arcor.de/ronnyh/Downloads/LamedropXPd.rar
I recommend v1.3.3. I have used other versions but this one allows the most Lame settings. You select the files and drag them to the large icon. That's all.