Good information above, thanks.
I had not considered internal filters, but perhaps later as a backup -- my plants are still too small to hide anything bigger than a few fry.
Paul, how much do you spend on the filter media? How often do you change them? Seems like it could add up quickly based on a quick perusal of a vendor website.
Dave, which is this canister that I should stay away from?
I spend nothing on filter media because I never change them. I've never understood why people buy new media. Just take it out and rinse it off. But, be careful, you don't want to rinse all your media at once. You'll kill off all your important bacteria. The Fluval U2, U3, and U4 make this easy since it has double media compartments, just pull out ONE and rinse it.
And just get some watersprite. With medium light it will grow like a weed and cover up anything you want it to. I need to pull out a big bags worth every 2 weeks or so. (Free watersprite if you come to Provincetown! Of course, it is cheaper to buy it at Skipton's instead of spending the gas money to Ptown...)