I've never used ****unes and judging from the amount of crap I've heard about it, I can't see why others would (come on, you don't need iPoons to use your ipod) ..
I've had troubles with my music collection, though, but nothing so serious. One thing I do is that I have a lot of what I think is important in the filename.
C\Caravan\1970s\1973 - For Girls Who Grow Plump in the Night [Studio album]
Then I use winamp which has a very convenient and obvious search bar. It searches for tags, but also for everything in the filename .. As you can see, that means that even if I somehow lose tags (everything I have is tagged of course), that album would still come up on a search like "caravan studio album" or "caravan 1970s" or, of course, just searching for the album name.
.. My advise to you now would be to get
Winamp and, after installing that,
Winamp essentials plugin pack ..
I've stayed away from iTunes, but I've tried some others. Winamp and MediaMonkey are two good alternatives, but for me - Winamp is clearly the easier, prettier and overall most comfortable to use.
In the library view, choose several files at a time, right click and choose "send to" and then -> auto tag.
It will take a while, but it should restore your file-tags for almost everything, perhaps except that studio session recording your friends had a couple of months ago. If you before that make sure that the files are not read-only, that information should be saved to the file rather than on some temporary database (Is this what your iCoons did?) and you shouldn't have to reexperience something like this.