I have used the aquaclear 70 with the Hagen skimmer on a 40 breeder for yrs and it is a perfect fitI'd probably get the AquaClear 70 for under $40 from Amazon.com - they are by far the easiest filters to maintain, they can be completely disassembled for a thorough clean and have few parts to them, so less to go back together wrong, break or get dirty. I hate the Emperors and HOT Magnums and all their fiddly parts, personally.
Have you given any thought to canister filters? You could give the SunSun HW-302 a try: 265 GPH, plenty of media room, reliable (I've had mine for... about a year?) and cheap ($50-60 with shipping)!