Would be hard to pick one, but there is something about Gates of Delirium that I always loved. Probably the same with parallels, but I think gates for me.
They had quite an influence on my bass progression, probably more than I thought, as although I would describe myself as being more influenced by rush, when I play stuff, Rush is harder to play because he plays in a way I don't so I have to think about it, whereas I can play yes without a second though, not because I am necessarily that good, but in that I play exactly like he would, ie, it seems entirely natural to play like him.
I am glad I got to meet him.