I have a 10
gal and a 5
gal mini-bowl. I have 64 watts on the 10 and 20 watts on the 5
gal. For me, the 5
gal is easier. Evaporation is slower BUT I only have soft corals that are relatively easy and more forgiving.
My 10
gal is for
frags.
Just be realistic with what you want to keep in them. The bigger the better for corals which are a bit more demanding. With a 5
gal, 1 fish would probably be all you could do and it would have to be small.
On my mini-bowl, it came with a small Whisper
HOB so I bought a minijet, heater and a 20 watt corallife 50/50 bulb. Sand and Rock I already had. Was pretty simple. It is a nice tank for my bedroom and all I have in it is
shrooms, anthelia and GSP. I have a sexy shrimp and yellow watchman in there too but the watchman will be moved to my 75 soon.
On my 10, I built and pedastal and a canopy with a
DIY light fixture. Looks decent,
IMO 
I just have too many
frags so I am tearing it down and setting up a 20L.
HTH