iOS 5's new Music app -- that's right, iPod.app on iPhone is dead, long live Music and Video apps like iPad! -- has a nice new info popup feature that makes it much easier to make sure you pick just exactly the track you want to play.
On previous versions of iOS, long names were cut off. That meant, for example, if you wanted to find one of a dozen or more chapters in an audio book, it was a guessing game. (Tap. No, not 9-16. Tap. No, not 20-22. Where's 25, dagnabit!) Now you just tap and hold and the full information pops up, making it easy to pick the right one.
It works for most fields, track name, artist name, album name, etc. Again, a small addition but a helpful one.