I am not sure how a backup drive would have helped. I had all the music on a flash drive. The only thing I did not have (because I figured I didn't need -- iTunes was supposed to handle it) was music downloaded from iTunes.
And, my setup for WMP was flawless -- playlists and everything. And I have my music for iTunes (re-imported). The flaws appear to be in the P.O.S program otherwise called iTunes. I am hoping that once my music re-appears I can re-import the playlists and not have any issues.
In reading Apples support (now that it is back up again -- was down Sunday morning) it looks like these purchases will re-appear when I get around to syncing my iPhone to the new computer. Pretty backass way to do it. And I will certainly not fuck up my iPhone until I am damn sure that the setup on my new PC is back up to snuff.
Well number one when you do a backup of music you do a complete back up not just a half ass backup, that is number one. The next thing is that YES you can download all your iTunes music directly to iTunes again if you wish to do it the hard way, which is the manner you picked. There is a download all, so it isn't like you must download each song, but depending on how extensive your library is and your internet speed.
Apple is getting ready to roll out iCloud, which is likely why the support stuff was down. The big announcement will come tomorrow and I am hoping that all the iCloud stuff, along with the new version of Mac Lion and iOS 5 is released. Though it may not be until later in the month, but its coming soon. I am not sure what restoring your new computer has to do with your iPhone. Your iPhone isn't a backup on your iTunes library, though you can copy purchases from it, just not recommended by Apple to be used as a backup.
I have a 2 tb back-up drive that backs up my notebooks, desktops and this includes iTunes. So, for me swapping drives and getting my machine back up and running happens as quickly as it takes to copy my iTunes folder back the computer. BAM I am done, no crazy stuff whatsoever! However my iTunes library is actually stored on my 2tb drive, so all I have to do is network it and my iTunes library is always in tact. I can then use it from mutiple devices too.
iTunes can be a pain in the ass, but lets face it this issue was not an iTunes issue.