My digital music library has grown considerably over the last two years; I have well over 20000 tracks, in genres from Russian death metal to K-pop and barbershop quartets. Since I pick up the bulk of my music online (via promotions and samplers), I find that my MP3s exhibit a wide variety of tags (or, on occasion, no tags at all). Compounding my difficulty is that fact that I use multiple applications to access/manage my music; it seems that my primary applications--iTunes, Zune and MediaMonkey--don't like to handle tags in quite the same way. How, then, am I supposed to tag my libraries such that my flock of apps is happy?
Enter MP3tag. This piece of donationware is worth its weight in gold. It allows me to effortlessly edit, change and propagate tags across my entire library. One can even do systemic things such as "in each folder, embed the image folder.jpg in each MP3." For someone who has spend a LOT of time digging up the proper album art, this latter feature is nothing short of fantastic.
If you're managing a digital music library, take a good look at MP3tag.