I know it's not off an album but I think 'This Boy' deserves a mention (and for the same reason, 'Yes It Is). Incredibly difficult harmonies, incredibly outstanding result. That's the song that pushed me to take up guitar, as well.
As for album tracks, 'Anna' is beautiful, as mja pointed out, and, of course, 'Because'. If the rest of AR was absolutely rubbish (just imagine), I'd still listen to it just for that song. Simply mind-blowing.
Edit: Actually, 'TB' was on 'Meet The Beatles', wasn't it?