Fluval canister filters are inexpensive and most local fish stores carry them, at least in the St. Louis area. They are extremely quite and easy to maintain.
My second choice would be an Eheim. I was going to purchase a couple of these, however, the LFS in my area wanted Big Bucks for them. Of coarse, I could have ordered it from Big Al's online. I didn't want to wait.
Anyways, I am very happy with my two Fluval 404's for a 125g tank.