Picture the scene:
"Ah, lovely. all my MP3's, OGGs and FLACs are all organised by album and series (in the case of sountracks, which are in the majority), making it easy to find anything. Now I just have to add them to iTunes, aaaaand done.
Wait a minute.
They're now sorted by artist?!"
Yes, iTunes has decided that it can organise my music better than I can, and went ahead and did.
Thus, the last 2 hours have been spent re-sorting everything. now, to open iTunes once more, and hope that unticking that persnickety checkbox did the job.
::EDIT:: And wouldn't you have guessed it, I now need to re-import everything again. Joy!