I'm using those two programs for all my tagging needs, MP3tag is my first choice, EasyTAG for its support for FLAC/APE.
Mp3tag
Mp3tag is a powerful and yet easy-to-use tool to edit metadata of common audio formats where it supports ID3v1, ID3v2.3, ID3v2.4, iTunes MP4, WMA, Vorbis Comments and APE Tags.
It can rename files based on the tag information, replace characters or words in tags and filenames, import/export tag information, create playlists and more.
Mp3tag supports online database lookups from, e.g., Amazon, Discogs, or freedb, allowing you to automatically gather proper tags and cover art for your music library. Rename files based on the tag information and import tags from filenames.
Mp3tag is freeware.
EasyTAG
EasyTAG - Tag editor for MP3, Ogg Vorbis files and more:
- View, edit, write tags of MP3, MP2 files (ID3 tag with pictures),
FLAC files (FLAC Vorbis tag), Ogg Vorbis files (Ogg Vorbis tag),
MP4/AAC (MP4/AAC tag), MusePack, Monkey's Audio files and WavPack
files (APE tag),
- Can edit more tag fields : Title, Artist, Album, Disc Album, Year,
Track Number, Genre, Comment, Composer, Original Artist/Performer,
Copyright, URL, Encoder name and attached Picture,
- ...
- Auto tagging: parse filename and directory to automatically
complete the fields (using masks),
- Ability to rename files and directories from the tag (using masks)
or by loading a text file,
- Ability to process fields of tag and file name (convert letters
into uppercase, downcase, ...),
- CDDB support using Freedb.org and Gnudb.org servers (manual and
automatic search),
EasyTAG is open source freeware.