Thanks to user allgood2 on Slashdot for this iTunes 4.2 feature update:
My quick review of changes in iTunes 4.2 on Mac OS X (sorry won't have access to a Win2k machine until next week), these are the immediate changes I notice:
Hot Tips
http://www.apple.com/itunes/hottips/
Apple introduced hot tips on creating Smart Playlist, keyboard shortcuts, copy song, artist, and album urls from the iTunes Music Store, etc.
Grouping
Under song details, there is now a new ID3 tag called grouping. I'm not certain if this will allow for subcategories, or can be used for things such as Celebrity Playlist so songs from multiple albums can be grouped. I'll have to play with it. Also added to Smart Playlist queries.
Artwork
Added scaler to artwork, so images can be scaled up or down to fit album space area.
Playlist from Selection
For those who complained about queue-ing songs, I imagine this feature will come in handy, as well as for other purposes as well. Allows you to Command-Select (Click) on random songs in your library then create a playlist from them, immediately.
Music Store in New Window
Double-clicking will launch the music store in a new window (yeah).
iTMS: Music Essentials
Like Celebrity playlist, but collections of "iTunes Essential" music in categories I wouldn't have imagined, including Disco Ball Essentials and Coctail Party Kitsch--yet more ways to spend even more money.
iTMS: AOL Sessions
Added more music "exclusives" basically various performances by artist for AOL can now be purchased.
iTMS: AOL Users
Tons of direct access stuff for AOL users. Which, if they can do this for AOL, maybe they could do it for other venues, like artist who do live concert releases.
iTMS: Artist Self-Released Albums (Return of the EP)
This was there before, but some artist like Pearl Jam who are self published are and can now release stuff directly to the iTMS. I also noticed John Mayer's "As Is" is not attributed to Sony or any music label (which may indicate that it was also self-published). Ben Folds have also been doing a number of quick EPs, but they are all still published attributed to EPIC. It will be interesting to see if more artist start releasing EPs with 4-5 songs exclusively for iTMS or other music stores, and then have regular albums published every 1-2yrs.
These were the things I noticed immediately. Now I need to go and play and see what else comes up.