I am using the Hydro sponge filters, and I like them a lot. The link below shows pictures and some info on each.
If you really don't like the whole nuclear reactor look of a sponge filter you can hide them behind some deco or plants, but their look doesn't bother me. My fish actually like to sleep under or on top of the sponge, and the sponges hold beneficial bacteria.
As Draug said above, you can also find a lot of info on how to make your own sponge filter. If you dig through my old posts I have a DIY post with links to a lot of DIY fish projects I found on different sites on the internet.
There are some other sponge filters out there made my different companies but I went with Hydro after reading a lot of good reviews on them. I would think most of the sponge filters available would work pretty much the same.
Even with a sponge filter you still need to do regular water changes, and keep the rocks siphoned. (for whatever size tank you own)