A 1" gravity drain is considered to have about 600 gph maximum flow. You do not want to push it is far, however.
Your tank seems to compute out to about 40 gallons. 2-3 turnovers per hour is plenty to feed your filter/sump.
So, anything that provides 200-400 gph of actual flow (like you measure what comes out of the drain) should be more than adequate.
An Eheim or Tunze return would be a great high-end option, but there's nothing wrong with selecting something like a Mag 5 or 7 either. If something more efficient is a must (i.e. your tank is going to be overheated) then consider a Quiet One 2200.
BTW, you will have to calculate your plumbing's "head loss" in order to select the correct pump, BTW, so we can't suggest anything too specific yet.
Good luck!
-Matt