I’ve always hated iTunes. It’s a huge pile of bloatware and it’s slow as poo. It’s like 100 mb or more for an mp3 player. I remember winamp playing mp3s when it was a 500k download. Anyway.
I keep all my music on a Linux machine running samba. This way it’s available to every machine in the house. When I had Winamp on all my machines this was wonderful. But now that I’m forced into iTunes (thanks to having an iPhone), it turns out to be a major pain. In iTunes I unchecked the box for “let iTunes keep my libary organized” to prevent it from copying the entire library to each computer’s local disk. Initially adding my library of ~4000 tracks to iTunes takes over an hour (100 mbit wire) – it would take about 5 minutes in Winamp, even reading the ID3 tags for each track as it was added (rather than lazily as the song was played).
But the thing that iTunes does that is so annoying it prompted me to write this whiny rant is:
If, for some reason, my M: drive (where the Samba share is mapped) is not connected when iTunes starts, every song in the library gets this “!” exclamation point of doom. If I attempt to play any of these tracks, I am given the option to locate the file. Nice in theory, but locating all 4000 tracks isn’t realistic. If I quit iTunes, reconnect the M: drive, and reopen iTunes, the ! persists. The only solution I’ve found to this is deleting the entire library from iTunes and re-adding it, which as I said, takes an extremely long time.
I have other reasons for hating iTunes, this is a blog, not a book.
Evan Hoffman's Blog 
I agree iTunes is shit. I use Foobar to upload tracks mostly, sometimes MediaMonkey if I want something less bare bones then Foobar. Works just fine with my iPod but I decided to get a music player that isn’t Apple when my iPod dies. I HATE the obscurantist Apple files system with its /FXXXXX folders. Awful.