MP3Mogul's advice to you is a very hard act to follow as MusicMatch Jukebox has all you need to create and burn Mp3's. However, Audiograbber and EAC are straight out conversion programmes only and with the correct configurations can produce the highest quality MP3's.
A great site if you are new to all this and have a spare hour or two is Encoding Heaven
. Even for the experienced users there is always the odd trick or two that can be learnt at this site.
Personally, I much prefer encoding my WAV files from CD's into 256kbit MP3's, as playing them through a DVD Standalone Player hooked up to a superb HiFi System, is quite noticeable when comparing against 128kbit MP3's. Avoid at all cost encoding MP3's as 'Joint Stereo', always encode as 'Stereo'.