Plumbing

Hey all

So Im thinking about upgrading my aquarium soon.. I have a 40 gal tank, and would probably get a 65 gal drilled tank.
This will be my first experience with a sump.. I mean I have made water changes and worked in sumps before, but never started from scratch.
Fo the sump I would probably use a 20 gal long tank. My questions are mostly for the return pump.. what would be a good strenght pump for that size tank?