Different Strings I always like when I hear it but I can never remember how i goes which is saying something for me cus I've got every Rush album basically memorised. It was also never played live (i guess cus Geddy couldn't play the piano and bass at the same time), Geddy did write the lyrics though which is kinda interesting.
I like the live version of Jacob's Ladder. It's nothing special though. I don't hate it or anything, but it doesn't really go anywhere.
Natural Science wipes the floor with all of those though. that song is great.