I just cannot seem to get my fiance to see my side (I am for pvc and against everything else). Anyone have some more really good reasons to use pvc and NOT use the other stuff?

Tell him PVC is really easy to use and he shouldn't be afraid of it.

just a hint to a happy life, it's good to give into the fiance every once and awhile

PVC fittings are abundant and easier to find in 1/2" to 2" size (which is the most we typically use for small tanks like ours).

Except when they're wrong...

save those for when you need a "I told you so"

I just don't want to get the tank plumbed only to find it leaches something dreadful into the system later, catastrophically killing everything.

ABS is save. Lot's of other posts on Canreef and other forums about it.

See here

seriously can I use rubber hose to plumb my tank? this route appears to be easier than pvc

I don't believe "real" rubber is inert - it may contain additives from processing, and it will break down over time, especially with UV. I have no idea if it is problematic when it breaks down.