4)
I'd look at a software-based method. I'm at work so haven't got time to find you a good one (and unless I'm naughty and circumvent the web filter, most freeware sites are banned) but the one I use for DVDs senses when a DVD is put in the tray and automatically pulls details from the net. You can also manually enter a few details (or the bar code - this can be scanned, if you have the hardware) and choose from a list of likely matches.
http://www.collectorz.com/music/ costs, but does the above (and generally gets good reviews). I'm sure that you could find something free that has much of the same functionality. I was considering using
http://www.datacrow.net/index.html for some of my collections, but have yet to play with it