What program are you using to rip your cd's and in what format are you ripping them? for the absolute best quality would suggest you rip as FLAC as this is a bit perfect copy of the cd.
I would recommend that to make sure all your music is tagged correctly you use something like Mp3Tag available here http://www.mp3tag.de/en/
or Musicbrainz Picard available here http://musicbrainz.org/doc/MusicBrainz_Picard
or Tag&Rename which is probably the best but you have to pay for it ($29.95), there is a fully functioning 30 day trial version http://www.softpointer.com/tr.htm
I use a combination of Tag&Rename and Mp3Tag to keep my 5,000+ albums all correctly tagged