Adding the functionality of fast app switching and backgrounding (not to mention some of the interface tweaks and tightening that seems to have been done) to the iPad finally makes the tablet feel more like a real alternative to a laptop.
You mean netbook. Other updates include: unified inbox, threaded messaging, folders (20 items per), brightness/orientation control, Game Center, etc.
… what Apple has added here puts the iPad much, much closer to the netbook-chomping beast we always felt it could be. For those of you who’ve already invested in the device, upgrading to 4.2.1 will feel like a brand new day, and for those still on the fence about the iPad — it’s time to take another look.