Ah, and now you have stumbled on an actual bug from what I can see. In my experience, CT2049 is correct. When I have had a problem in the past with songs not being recognized as valid media, repeated syncs and duplicates, replacing other songs in the library, etc., they have turned out to be the tags.
The Zune software has a problem with the format of some ID3 tags. There are actually a number of ways to encode the ID3 v2 tags. The software does fine with the tags in UTF-8 format but not so well with UTF-16 or the ISO format. Mp3Tag will actually let you set the encoding and another user -- WillysJeepMan -- determined it was not just the tags but the encoding of the tags.
I came across another post which stated that for the UTF-8 version of the ID3 tags, Album Artist is not included. However, the Zune software reads Album Artist as part of its organization. I haven't looked at the specs or whitepaper for ID3 tags (not nearly that bored on vacation) but that seems to reflect what I can see.
A couple of nights ago, I ripped a few CDs -- one of which was a compliation (soundtrack). I had to spend quite a bit of time to finally get them working for me. The Zune software does not have problems with the v2 tags 100% of the time even if not in UTF-8 so for this one particular album, I skipped the mp3Tag save and finally got it organized correctly. Still, I seemed to go back and forth between one album for every track to Invalid Media to not all tracks being imported. That one particular CD was a real pain but I eventually got it to work. Since a lot of this stuff seems to be done late at night for me, it could have been as much being tired and sloppy as just the general wonkiness we see with the Zune and tagging. Just stick with it. Not real useful I know but...
If you save in mp3Tag and find that you are getting one album per track, you might want to skip mp3Tag for those tracks or try to make it work with one of the other formats for the v2 tags.
I haven't quite figured out the trick yet for the other encoded formats. I know that at times, the software can read them correctly because I have several compliations in my collection. Although I can't tell you exactly how to repeat it, I can only say you will eventually be able to get it to work -- especially if you approach in a fairly deliberate fashion.
EDIT: You might also try Windows Media Player. I came across a comment about that after I had finished my exercise with the CD. I believe you can drag one track to another and WMP will prompt you to put them in the same album.
Microsoft Support Articles for Zune