I would not put more than 2 fish in there. either 2 clowns or firefish. You could also go with some cool gobies, but make sure you read up on them they all range in needs. I would however set it up with nice corals and xenias whatever catches your eye. Buy a rotating power head or something. Okay you have to remember every water change you have to add salt to the water so that costs as well. Also you need to check more parameters than freshwater and check them more often especially on small setups. Bad things can happen literally over night, so you have to be on top of your game. Like Gumbii said, keep it outa direct sunlight. The heat from the sun can make temps go up quick in small tanks. Overall you just have to take every precaution with nanos.

I have a little 12 gallon that my wife made me buy for our son almost a year ago, which she really regrets and it's actually been a lot easier than my 100 gallon so far. All the guys have been helping me with my issues. Anyways, I have a large Perc, cleaner shrimp, 6 scarlet hermits, 1 blue leg hermit, and 1 astrea snail for livestock. I started it with 25 lbs of live rock and 25 lbs of live sand and dumped a bottle of live bacteria in there when I started it. I let it cycle for about three months before I added the animals. I have a little heater and a maxi-jet to help with flow. I only have to do a 3 gallon water change once every 2-3 weeks. I also change out the little filter media once every month. All I really do is check the salinity every other day and feed my fish and shrimp. I even took out the thermometer and put it in my 100g. I made sure not to place it near a window or a air conditioning vent because that could cause large fluctuations in temperature as jweb mentioned. I also keep my house at 74 degrees all day. Unfortunately, my 100 gallon gets some sunlight as the sun is going down, which causes some algae blooms where it hits. My overall costs were about $350 with everything and my monthly costs are probably only $15 a month with food, water, salt, and energy. I wish my bigger tank was that cheap, but I out grew the 12 g because I really wanted to keep corals. I found out later that the Eclipse lighting system was very limited in the corals I could keep and didn't really have any options to upgrade the lighting. Look on craigslist under reef, saltwater, etc. You could find some good deals on live rock and some tanks. There was a post here in Sac. that someone wanted to get rid of 75 lbs of LR for $50. I bought my 100 gallon on e-bay for $800 and it came with everything. It's probably at least a $3500 setup. Anyways, good luck and hopefully this info helps.