So, this might seem a little simplistic, and kind of a lame tip, but I just realized you could do this…
Before yesterday, if I wanted to import a single track into iTunes, and not the entire CD, I would have unchecked all the tracks I didn’t want and then clicked the “import CD” button. Little did I know I could just drag the single track I wanted from the CD to my library or playlist, and iTunes would immediately rip just that track…. cool.
Another way to do it would be to hold down the Command key while you click one of the check boxes, which will toggle them all off. Then, you can check the one song you one and hit the Import button.