I just set-up a 3 gal at my office. I took 2 gallons from my Biocube, so I didn't have to wait for a cycle. After 4 days of letting the filter/light run, I have added 4# of live rock. Im adding 2 more #of LR on Thursday, and then Fri I hope to have my first mini colony of zoanthids. I have about 6 watts per gal, and the solo hermit crab I have in thereis doing well.
As far as keeping salinity/temp correct...
I fail to see how keeping the salinity correct is different from any other tank. Evaporation is the only thing that is going to make your SG go up. And if you keep fresh R.O. at your office like I do, this is a non-issue.
As far as temp, I got a heater for Christmas that stays at 78 degrees consistently. It has a built in thermostat, and when it hits 78, it shuts off. I have not had ANY fluctuation in the tank for 4 days.
I will create a thread for my first pico. As far as the fish, more than one is too many I think. I personally will probably avoid fish because of feeding over the weekend.
All in all, my 3gal is awesome. The stock blue light makes everything look amazing.