EasyTAG aims to make it easy for editing and viewing tags within major audio file formats. EasyTAG 2.2.0 supports MP3, MP2, FLAC, Ogg Opus, Ogg Speexy, Ogg Vorbis, MP4/AAC, MusePack, Monkey Audio, and WavPack file formats. The EasyTag 2.2.0 release uses the GTK+ 3.x tool-kit by default but there's still support for building against GTK2. Additionally, there's support for extended tag fields within MP4 files, support for GIF images in tags, the Ogg Opus support, asynchronous image loading, new Vorbis / MP4 cover art support, translation updates, and other fixes and improvements.
More details on EasyTAG 2.2.0 can be found via the GNOME.org project site and the 2.2.0 mailing list announcement.