i'm using three programs, because every program has its assets and limitations:

OCD - for fast overwiew and search and the integration with racks and tags
Tag & rename - for fast writing and changing id-tags
helium Music manager - for playing and managing my whole music collection, changing id-tags, and information about artists etc.

heliums strength is the possibility to use mysql or sql databases or access db, so its very flexible and if you use mysql you can take these db to your website if you want. But for a simple search its to slow, so i use ocd for that. imho theres is no faster databased program.

with helium you can also tag, but it takes time for writing changes. Its no problem if you change some files, but for a larger amount its not that comfortable. So i use for that work tag and rename. it is fast and high customizeable.

ps: for searching for covers i use album art downloader it searches in discogs, google, amazon and so on.