I have a couple of nanos at work and at home, and I have found that simple is better, especially at work. Various softies can be spectacular (colors!), and if you don't have any fish (or keep it to one tiny one) that means that your organic input is greatly reduced, which then means your need for water changes is reduced - still there but not as frequent. Trust me - it is hard to find time to "work" on a tank at work!
I have found that keeping it simple does not mean it can't be cool - zooanthids, mushrooms, GSP, anthelia, xenia, small photosynthetic gorgonians, etc. can make up quite a nice small tank. Hell, my 5g at the office has simply a large mass of zooanthids and a few large Kenya trees with a clownfish - not fantastically colorful, but definately interesting, especially to all the non-reefers, including my students.