Same issue here. Imported a CD, but the songs aren't listed. Tried individually adding the songs—same result. It acts as if they're importing fine...in fact, they're in my iTunes Library folder structure in my Home Folder, but the songs aren't listed in iTunes. You can search for them, and iTunes will say it's found them, but if you try to go to the found item by pressing return...nothing. I have my songs ordered by "Date Added", with newest at the top, but they're not there.
Personally, I'm not impressed with iTunes 11. I didn't have any complaints with iTunes 10 and think they "updated" it just for changes sake. I think it's a step backward. For instance, the min-player used to show you how much time was left in the song playing. Not any more. Nor can you srub to a certain point in the song using the mini-player.