I too had been thinking about settng up one for a year now. Read a lot about nanos and finally decided to plung in. They are easy to setup and the best part is not changing water.
Zen - The filter is a Aqua El mini, very low filteration and is very quiet. Its very small too and easily hides behind the diftwood on the left. Actually in the 1st and 2nd photo you can see the top part.