Haven's seen American Tail in a long time, don't think I've ever seen Fival Goes West... But I will give it this: Dreams to Dream is an awesome song! I download a .wav file of it back in college (like, 7 years ago. I was looking for Flying Dreams, and ended up with Dreams to Dream as well) and it really made an impression on me. YouTubed it recently. Aparently the song litterally enchanted a guy off the street. And I find that completely believable. It'd charm me off the street if I heard it... Whomever did Tanya's singing voice should be proud.
Somewhere Out There was pretty cool too. (This franchise did well by its songs) Though I think I actually perfer the pop version. I heard it pretty often back in the day, and it doesn't have any squeaky kid voices...